omg not this shit again : <

The one without 1.1A on it has a little tiny bit of poo inside it. Just a tiny bit. You can't remove it safely though as its embedded into the microchips. Other than that they're the same.

Edit: Feel bad about that :/ I think theres 3 versions:
1.0
1.1
1.1A

The 1.1 and 1.1A are the same, but the 1.0 apparently isn't, and I think thats the one without any version number, and apparently isn't the same inside (sensor not as good), but I also heard that there aren't any version numbers on some 1.1s as well.... :p

Should've just left it at poo. That was golden.

1.1a = OEM
1.1 = BOX

IIRC

The 1.0 has a low malfunction speed and will skip if you move it quickly - stay well away from it. The newer revisions can tolerate much higher speeds.

Where can you get a 1.0 nowadays anyway? Get a white one with 1.1 label or a black one.

http://www.ebay.com.au/itm/NEW-Microsoft-Whee...336719dba0 Is that a WMO 1.1? o.O

yes

There are some black WMOs that aren't labeled on the bottom but they perform exactly the same. I highly doubt you will ever stumble across a 1.0 model.

I had a 1.0 - it skips when you move faster than like 5cm/second