This mouse is sold for around 20€ at the moment, so I got one and give you a review.
Good and bad points in order of importance:
-high max. speed at lower resolutions (around 3 m/s)
-good thumb buttons, 7 buttons total
-software to save complex macros to the internal memory (no drivers needed)
-dpi configurable, and changeable by button on the fly
-build-in 1000 hz USB polling (adjustable: 125, 250, 500, 1000)
-not too heavy (you can also remove a weight inside to make it 90 grams; picture in comments)
-comes with 2 sets of replacemet feet
-high lift-off distance depending on surface (it is fixable, I explained in the comments)
-smells really bad out of package-> gone after 3 days of ventilation
-trojan TR/Dropper.GEN on driver cd (bummer man!)
-Mouse test program ("Mice Judge") is not XP certified, results are dubious
Technically the mouse is really sweet (btw. I am not affiliated with A4tech). It's software lets you build your own setup and macros and store it into the internal memory of the mouse. That way you will not need drivers, the mouse works nicely with XP default drivers.
The shape is good for me, while maybe not perfect, a little wide at the back ;). A good trade-off between not ambidextrous but not too weird either.
At 400 dpi the max. speed goes up to ~3 m/sec and higher, but because the "Enotus Mousetest" I tested it with is a little flawed right now I can't tell acurate numbers, the direction is clear, you can't skip this mouse at 400 dpi. At higher dpi the max. speed is still over 2 m/sec wich is enough for most gaming setups.
The max. dpi is just ridiculous, noone needs 3200 DPI, but it comes for free so I don't mind. You can chose different dpi settings (6 in total) in steps of 1 dpi (even different ones for X/Y axis) by software, upload the setup to the mouse and then activate them on the fly by pressing the dedicated button. The mouse had problems with some settings I tried (like leaving out dpi settings or mixing them up), but generally it worked fine, looks like a minor bug.
It comes with replacement mouse feet, 2 sets, that's a great idea. I hope every mouse company will do this in the future.
Now to the bad sides...the smell...is disgusting :) I think I will ventilate it for a few days before I even really start using it, it's that bad. *After 3 days the smell was gone so I could use it.
It seems like the lift-off distance varies with the brightness of the surface. On dark surfaces (cloth mat in blue or black) it is rather high. Nothing you can't get used to since it does not result in unwanted movement, but not perfect. On really bright pads it is good.
You can fix the lift-off, I explained in the comments.
The trojan on the driver CD is just weak. I mean, WTF? This looks like sabotage, or they didn't even take the time to scan the data once before mass replicating it....dunno. But Antivir warned me nicely, so I copied all but the infected file to HDD, started the installation routine from there and it worked fine.
Mouse prediction/correction - while some find it bad and it hinders their aim, others don't mind/care or even like the feeling. It's a matter of preference. If you are unsure you could try the older MS mice models for comparison, those don't have it.
*I had to edit my conclusion once more after using the mouse on and off for a few month.
Here is my conclusion:
It's a good mouse considering the price and the fact it uses trusty optical led illumination technology over bug ridden laser-optical technology.
The software works well, but there isn't much use to the advanced options either. Makros are a nice gimmick but that's all they are, a gimmick
Personally I got fed up with the shape, simply put it is bad for anything else then palm gripping style, which I don't use.