You wouldn't know it by looking at it, but the Sandio 3D Game O2
is a comfortable mouse - probably one of the more comfortable ones I've used in the past few years (the only thing that matched it was a well-worn in Logitech wireless... but again, I'm getting off topic...). The idea of comfort is thrown off by the two ledges hovering over the awkward looking thumb sticks attached to each side of the mouse. When you first place your hand on the mouse, there's initial discomfort as you try and figure out exactly where to place your hand. It's a bit like your first kiss when you tried to figure out where your nose went. But, like that first kiss, you eventually find a comfortable sport and enjoy the experience.
The actual, practical use for these ledges and buttons differs depending on what you're using the mouse for. When using it for general usage, the ledges offer a nice gripping area that makes it much easier to steer the cursor around or pick it up when you run out of room on you mouse pad. This also helps during gameplay, especially when playing an RTS.
The thumbsticks aren't practical for general purpose applications, but work great when playing an FPS. Each stick is positioned in a comfortable position and rubberized to make sure your fingers don't slip off. When playing an FPS, you can move each in a specific way to make your character move. For example, pushing forward with the right stick and pulling back on the left one makes your character turn left. Again, there's an initial awkwardness that goes away after a few minutes of use and some training. The thumb sticks also serve a purpose in other games by acting as programmable macro buttons.
Another nice feature is the attachable back fin which acts as a palm rest. As with everything else on the mouse, I wasn't sure if I would like the fin, but it actually become one of my favorite features; not only did it keep my palm from dragging all over the mouse pad (which is one of my really bizarre personal dislikes) but it also added a little speed to my in-game reaction time. The fin nearly doubles the Game 02's length, which can make it unwieldy on some desks (like the podium in my classroom), which was the feature's only drawback.
As far as response goes, the Game O2 is great. It supports up to 2000 dpi, which is indicated by color of the mouse wheel. The first time out with the Game O2, I found it to be a little too oversensitive, but this was another thing that I simply got used to after playing around with a few applications. The mouse worked best for strategy games; the sensitivity was spot on and the added macro buttons really helped to speed up some functions. As for shooters, which the mouse advertises the most, the performance depended mostly on the game. For slower-paced shooters, like Stalker: Shadow of Chernobyl it worked well, though for something a little faster, like Unreal Tournament, it took a little more effort.
As far as non-gaming performance, I was really happy once I wrapped my head around both the mouse's feel and using the thumb sticks. Being able to quickly rotate around objects helped to speed up design. I actually became so used to using the sticks that the first time I went back to a traditional mouse, I had to think about some basic keyboard commands.