ergonomics perfectly suited hand

TMS / RSi:
Having occasionally MSD / RSi on the upper right arm, there a dozen years back, I definitely dropped the non-ergonomic mouse to move to 100% use trackball, as much at home and at work.

Query:
The choice to buy that M570 does not come easily to me (besides all my different trackball always work), but rather in order to "discover" the ergonomics of the new trackball pushed me to the purchase thereof.

Use:
True to spend 10 years of intensive use trackball to "doitgs" with the ball in the center as the Marble Trackman® or the Cordless Optical TrackMan a trackball to "inch" as the M570 with the ball on remote the thumb is not so obvious as this for the brain.
The first two days were frankly hazardous see funny, but after three days, the use of this new M570 have become intuitive.

Ergonomics:
The position of the hand is very relaxing and perfectly suited to its slight incline from rest position. The various buttons are well placed and fall directly under the fingers. The existence of roulette also urged me to buy this model. No worries on that side. The use of the thumb is perfectly suited for horizontal movement and since I only have screens 16/9 This corresponds perfectly to the most used in the day trips (two-screen work).

Reproach
One: slightly increase the size of the trackball for large hands.

Conclusion: ==> 5 Stars
I still wait a few days, but I think I'll order another one for the home. This is a good product, with very good ergonomics for the hand