Haven't been following the scene,but a card equivalent to my 7950 @ 1100/1575 should suffice for all your needs. I play every game nearly on ultra, including the Witcher 3 with very few settings on lower settings for a good fps.
Have played only one game with it, social stuff took over in my life past couple of months.Been using it daily for word/excel things,video editing and general browsing and i'm just digging the shape a lot. The sensor feels very simular to the 3988 so no need to adjust. The clicks are just superb. Going back to the DA, I can't handle the soft clicks. The harder clicks are PERFECT , mainly their clickiness, it's so bouncy and has a a good tactitle feedback.
Umm... I can aim the same with both,except I find the EC2-A more comfortable. What I did was change my sensitivity because DPI steps are different. I used 1000dpi,0.8 in game with the DA. Using 800dpi on the EC2,though not 1.00 in-game ,but 1.035 because of the different DPI steps. Do that and once the muscle memory is back,you'll rekt ppl again.
Shouldn't the EC1-A be better tracking wise than the G400? 3310 is a pretty good sensor. I used a DA before the EC2, sensor feels identical (3988 vs 3310) . Only the 3366 I was using with the G303 felt snappier.
It'll work flawlessly with claw grip.When it comes to fingertip grip, I'm not sure how you hold you and how forward/backward your fingers are. I think it should work,vertical movement is somewhat limited,around 1cm of pull down ,at least for me with my fingers placed on the middle of the MB. If I go and hold it towards the back of the button,there is more.