The problem with a new mouse always comes back to the 'break-in' period, actually getting used to a new grip. Unless you buy an identical mouse, there will always be a transitional period - even if you buy something 'similar'. That period is about 2 weeks of regular use. Your hand will be sore for the first couple days typically. If you still have problems after 2 weeks, then yes, it may be worth switching to something else.
My first gaming mouse was actually the trend-setter, the Razer Boomslang; ambidextrous, massive buttons, flat and long, took me a while to get used to it, switching from the array of arched mice that is most common today. The second one I used for a good while was the Razer Lachesis, which is similar to the DeathAdder.
At the moment, i'm using that
R.A.T.7 and that can certainly conform to a flat and long mouse but with the benefit of the 'pinky' rest - for your little finger. After using the rest as a hook, it works well for high DPI settings, since when you go to clench your hand, your little finger is one of the first fingers to move, so quick back movements become easier to perform. Just wish the software was a little better.
As for the Corsair M60, we'll be getting one of those in to review soon, along with the other peripherals in the Vengeance set (M/K60, M/K90), so I can look into any areas you have concerns over. The CM mice, you'll have to ask Rob about.
With regard to mechanical differences, I'm no expert, but I can give you a rundown of what the basic differences are. There are 4 in total in the Cherry range, going from
Blue,
Brown,
Black and
Red.
Blue and
Brown are the traditional non-linear 'typist' switches which have the mid-way 'bump' for feedback.
Brown is the lighter switch of the two, requiring less pressure to activate.
Blue also has the very audible 'click'.
Black and
Red are the linear switches with no 'Bump'.
Red has the lightest activation pressure with reduced noise (and most expensive),
Black is a stiffer key type with reduced noise. So for gaming, the 'best' switch is
Red, due to low noise, no feedback, linear and minimal activation, it's just very hard to get a full keyset with them.
The only other keyset worth mentioning is the Topre keys, which are rubber-dome capacitive switches which are the quietest of the lot, but with feedback for typists.
