It's a pretty solid Quake 2 sequel, and i'm glad to see the Quake fan base has warmed up to it over the last twenty years. It is essentially Quake's equivalent of Doom 3 in that it's slightly slower paced with more of a "horror" element than the pure action of the previous titles, but it's certainly not a bad game.

quake 4 its like doom 3

Pretty straightforward, kind of boring. Love the graphics (Doom 3 engine is nice), even if the textures for whatever reason are a blurry mess. Weapons, gameplay, and the enemies aren't really anything special, and nothing is noteworthy.
I like the extra dialogue you can get if you keep pestering the other marines. All of them are busy and can't talk right now :(
Exploring what little areas the base ship lets you walk around was pretty cool I guess.
I want to find more things I like about the game, but there isn't really anything that stands out to me.

To compare this game with Doom 3 (a survival horror) to Quake 4 (a more typical run and gunner) is not a fair comparison, but since they use the same exact engine including the dark as hell lighting and grungy atmosphere it's hard not to compare them. I was looking forward to Quake 4 after seeing how much it looked like Doom 3, and all the classic old studios shown in the beginning seemed like a sign of something good, but so far it's been very underwhelming.
At least the game sort of picks up after you get stroggified. You move faster, and the environments get more bloody. But it isn't enough to save the overall game from being lackluster.
Quake 4 makes me want to play through Doom 3 again.