The top two buttons are also set quite high on the most bulbous part of the mouse so you have to remove your thumb and reach them, which is a little awkward. Towards the front of the mouse are buttons for volume up/down and mute. Being able to control volume this way without having to move to the keyboard is great, though I found that to reach the volume up button at the front I had to reach down a little. The side buttons, which default to forward and back are easily reachable from the thumb. Of course, it all depends on hand size, but generally I found the feel to be good, though not quite as good as the MX Revolution did (though of course the caveat with that mouse is that it’s right-handed so I couldn’t use it).
As well as the usual scroll and click, the mouse wheel can also be moved from side to side, useful for web pages and Excel. I found that it didn’t click as easily as my regular Logitech wired mouse and I work harder to get it to do so. I also had to alter the setting in the SetPoint software, which defaults the middle button to a zoom function, which I found a little odd – clicking is much more useful (e.g. wheel clicking links in Firefox launches link in new tab).
Of course many people will be wondering how good the mouse was in games. I tested with short sessions in Day of Defeat: Source, Counter-Strike: Source and a bit of Half-Life 2 single player. I found that mostly I needed to get some practice in, but I was satisfied that the mouse wasn’t really the problem with my lack of success. I still feel that hardened players of twitch games will be better served by a faster dpi mouse, which for left-handers will mean going wired. If you’re more of a casual gamer though, the MX610 will be acceptable.
Actually having a contoured mouse felt a little unusual to me but I quickly got used to it. Even though I use my on the left hand side of the keyboard I have always kept the left and right click buttons the regular way round. However, on this mouse I felt comfortable to actually switch it around, as the index finger is faster for doing those left clicks.
It may not be quite perfect but not having had the luxury of using a contoured mouse before, I have to say that I was very happy with the MX610 for lefties. Economies of scale inevitably dictate that the left-handed version will be more expensive than the right but thankfully it’s only a few pounds more. I can quite happily recommend the MX610 for left-handers and not just because there's no other choice.