This game has some funny little bugs that you discover as you play, but I still love playing the multiplayer with friends. Plus there's a bunch of characters to choose from with lots of customization options. Would recommend on sale :)

Last I played this in 2013-4, after all DLC with the extended ending had come out, & I remember liking it a lot as a send off for ME, but then I made the mistake of going online & it made me feel a mixture of shame, confusion, apathy, & over the years I've distanced from ME3, especially since EA (& Bioware) continued to go downhill so easier to see their later stuff following the same trend.
Got the urge to replay ME1-2 & felt like it was time to finally revisit ME3 in over 10years.

DISCLAIMER: I have a habit of checking PCGW & other sources to make sure I install any unofficial patches & other hacky solutions to get a game to run smoothly with some QoL stuff thrown into the mix if available, ME1&2 were no different, played them with ME1Recalibrated, MERLIN & some other smaller stuff, ME2 I played with Early Recruitment & Project Variety (very crashy still sadly), & when it came time to install ME3, checked recommendations, it had an Unofficial Patch by Orikon, but I did the mistake of reading more on their description, where I found out they also made "Enhanced DLC Integration" which felt like a no-brainer, but then the rabbithole deepened as they also made "Immersive Thessia" & Final Confrontation - Priority Earth Overhaul mods, which when I read about were too hard to resist.
As such, my impression of replaying ME3 is heavily colored by those mods, Thessia, the final Earth push were indeed some of my favourite missions, having the ending this dynamic squad growing with Grunt, Kirrahe, Zaeed & Jacob joining you on the final push to get to that tower, with some Geth Primes dropping in to assist and other troops mirroring your alliances, really elevated the final stretch.
So this isn't a vanilla ME3 review, this is an Orikon-favoured ME3 review.
(Though I still think the core has some really good stuff in it which I'll get to)

The ending does still kind of feel a bit lackluster, I wish they had for instance after your crew puts Shepards name on Normandy's memorial, a brief moment where the camera follows say Garrus & Tali to the Lounge where they'd reminisce a bit about a few moments they shared with Shepard, maybe Javik would awkwardly try to console Liara for a bit again with some memories of Shepard, Joker with EDI, all dependent upon player choices & playstyles over the trilogy, then cut to credits, that would have been a softer way of ending (true ending being the friends we made along the way lol, less green/blue/red colors). But having watched on YT how the original 2012 endings were, I sympathize with how angry that not doubt made many fans playing ME3 day 1.

BUT, I think pretty much everything else in ME3 kind of feels good & fitting, where a trilogy like this with the setups it has would end up paying off, everything from Turians-Krogan-Salarian conflicts & resolutions to Quarian & Geth resolutions, to the DLC; Ashes, Leviathan tying nicely into the main mysteries of the universe (mod maybe helped integrating), Omega & Citadel being excellent fun flavour, many side missions are also nice little flourishes which at times have cool surprises. Your squad still feels like your squad you've had over the trilogy, the writing is still in most parts on par with the previous entries- Of course ME3 is more brooding, melancholic than ME1&2 were, but that's by design with the events and also being the conclusion to the saga, a goodbye to characters & a world that many grew to like, it's earned I think, while still having those lighter moments that feel fitting for people looking for ways to find comfort, distractions & strength in the universe they find themselves in with their friends.

There's one thing beside the ending I wish was better in ME3; giving the player just a tiny bit more conversational freedom. In ME3 they removed a lot of dialogue choices, sticking to paragon-renegade options at key points, with rare investigate options, & outside of those most cutscenes play out linearly, with occasional par-ren-interrupts. It makes for more dynamic scenes where NPCs & Shepard aren't just standing around scratching their noses waiting for the player to pick their lines, & I sympathize with devs trying to cut down on awkward repeating scenes of NPCs standing around grinding the pacing to a halt because a player wants to investigate about some background info while reapers are tearing a city into shreds. Still, I wish we'd gotten even just 15% more options than we did, at least a few more neutral friendly options instead of heavy flirting or be a d/ck with some squadmembers.
I do actually kind of like the Half-Life-esque approach to some dialogue, where not every conversation needs to be a cutscene-like setup, but just players freely walking around, interacting & talking there seamlessly within the gameplay, I think it gives needed range within interactions so that some can be more obvious casual "exhaust their dialogue options & come back later" to "you are now given choices & interrupts to define your character"-- Plus, finally, squad mates actually move around & don't just sit in their designated spots from start to finish of the entire game, interacting with each other on occasion, even romancing each other which feels fitting for them.

Having just marathoned through ME1-2 within the last month+, I'd say ME3 was gameplay wise also the most fun, the third-person cover shooting feeling more refined than ME1&2 combined, rivaling pure third person cover shooters even in terms of snappy movement, controls & punchy combat, Gears of War can't boast about having a ton of cool class abilities with biotic & tech powers, the combo explosions & squad mate abilities, weapons feel a bit more refined (though I miss heavy weapons from ME2), (enemy) AI is decent, encounter design is fun.
I wish I'd live in an alternative timeline where the ME Legendary edition had the devs go through the effort of porting ME1&2 to ME3 gameplay engine (ugliest thing about OG ME1-3 is not how they did their post processing [well, I could do with less DOF, vignette & some lens flares toned down], but the butchered UE3 dynamic shadowing system thanks to Epic downgrading from UE2.5, other UE3 titles figured out how to put cascading shadow maps into UE3 much later into its lifecycle. Seeing CSM shadows in ME trilogy with cleaned up effects, textures, in ME3 gameplay engine, would have been awesome, but sadly just a dream).

ME3 was the more stable experience I had out of the trilogy, but there were a few awkward scenes even with the Unofficial patch where in conversations characters were facing the wrong way, or looking at the wrong thing, Shepard & Liara's gaze locked following Glyph in her room as it circled around & went to skulk in a corner, but then continuing your conversation about other subjects still Shepard & Liara just bending their necks trying to lock onto Glyph, it was semi frequent enough, ~5-15% of conversations maybe even in this 50+hours in my playthrough, ME1&2 wasn't immune to this sort of jank, plenty of scenes where NPCs had troubles going to their designated spots, how they would hold each others hands or what to look at, but it felt a bit more frequent in ME3. Another semi frequent minor issue was audio, at times it seemed like the engine had trouble with multiple sounds playing at the same time, tried increasing "maxchannels" in the coalesced bin from 32 to 64 to 96 but it didn't really help.
Another downside of ME3 on steam is EAapp, but there are ways around it, you won't get achievements, but I don't care, I just don't want EA's bloatware anymore on my machine.

As a ME1-2 fan I recommend it, with caveats, I remember liking it in 2013, launch was no doubt a disaster & a sign of EA meddling getting even worse by the minute, but as a full collection in 2025 with Orikon's mods it felt like a worthy conclusion to this saga I've loved since I played the wonky bad PC port of ME1 in 2008.