i own a g700 mouse.my grip style is based on games i played. claw for fps and palm for other games.
fps use claw grip coz faster reaction compared to palm. this is based on my opinion.
i think it best to go some shop that offer mouse test to find the suitable mouse for u

well i bought my g700 without testing.i just saw it at some video review and decided to take it up coz the function it offer with it price point is too good for me so i guess luck is on my side coz it fit for me.

ps. i cant test the mouse due to my location dun have shop that got demo unit

ya it is really comfortable for me as i can use it for hour without feeling any sign of fatigue which is impossible with my old cheap mouse. g700 is my 1st gaming mouse so quite happy using it
i would recommend someone who want ergonomic mouse should consider g700 for it price and function that it offer.

i buy it from lingloong and bundled it with razer vespula it cost me around rm350 if not mistaken.
for the lag, normal usage i dunt feel at all, but if i in gaming mode i usually go for wired coz just in case battery dies i during gaming.
middle button i rarely used it as i onli use for scrolling.dual mode scroll wheel is what i like which help me alot esp i used toggle it alot between uses.
battery i dun recall how long it last cause i usually charge it everyday during i game.
the wire that it come with the mouse is very thick and stiff which i dun like cause alot force needed when in wired mode. so i use another cable to replace it

ps. my logitech wired cable is broken now due to my 2 yr old cousin toy with it during my absent

middle button is not hard for me. but that depend on force exerted by each person so i really cant say about it.

it weakness for me it the original cable that come with it due to the stiffness that cause more drag needed on mouse.
battery is another issue as it is high performance mouse so it consume alot. u can use it about 3day b4 need to charge

i think is benefit cover up all it weakness