A lot to talk about...but for a free MMO game in a star wars universe it is amazing and so fun!

As F2P player you can explore 8 different classes and their stories plus 2 first expansions for the game for free!!!
lots of hours of content including the class story, planetary quests series side mission exploration mission bonus series.
And also a lot of content to play with friends: Warzones as PvP, Flashpoints as group effort challenges, conquests with guilds.

The game constantly recieves new content: multiple events with their own lore and missions, changing every month.
expansions for the game that adds hours of content, achievements to hunt for and explore all the planets, lore, beasts, world bosses and so much more.

While subscribing (monthly pay) to the game isn't a must, it is extremely helpful and will boost your gaming experience by a lot. It unlocks all the expansions for your account, gives you multiple boosts like XP rate, expanded inventory and money cap, unlimited warzones and even more end game content like 8 or 16 people operations on multiple difficulty levels.

My suggestion is this...if you wanna just try out the game to see if you like it, go in as a F2P and play one or several classes, get a taste for the game's universe, the community and its mechanics. If you like it, subscribe for a month or two and see what it's like to unlock the full potential of this game and its content. From there, decide whether or not to keep subscribing.

May the force be with you...