Honestly. Don't bother with more than 500GB. You'll only need frequently used programs and most played singleplayer games on there. SSD's wont magically make your FPS skyrocket. You wont need to put multiplayer games on there because your toaster scrub teammates still need to load in regardless of your loading speed.
A SSD is a SSD. Nothing special to it. They're all good enough.
Samsung Evo's are great, Corsair makes some decent ones as well. Just go off of reviews honestly, you'll see improvements regardless as any SSD is better than a HDD. Good luck!
As for gaming.. Well just get one that is a large space, ie 1Tb. 2Tb models cost a lot more than they should so I would recommend multiple 1Tb SSDs.