More specifically the tread (is that the difference?)

They used to look like this:

They got singletrack recommended and along with their other comments I was looking to buy some

On the web they now look like this:

How do they differ in grip/handling/cornering/braking/rolling/etc etc .. ?

Also, how do the 2.25″ and 2.4″ versions compare to other tyres?
[for eg 2.1″ Kenda Nevegal, 2.2″ ACX, 2.35″ High Roller, 2.25″ Advantage .. ]

They appear to work much the same. I may be an insensitive oaf, but I’ve got one of each on at the moment, and couldn’t really tell the difference.

The top picture is the old version, the bottom the 2008/2009 version.

The difference between Evo and non-Evo is to do with compounds.
Evo uses triple compound, where as the non-evo is just one compound all over. The evo version is better, and obviously more expensive.

The newer version is a much better tyre on the front. The older tyre used to wash out on loose ground far easier. I’d go for the new version every time.

The tread has changed, but that’s not the Evo/non-Evo thing. Evolution relates to the make up of the casing, not the tread, although I didn’t know there was a cheap version without the Evolution carcass.