Picked mine up this afternoon and have installed it and taken two vids. Before with the original 18T ratchet

http://www.youtube.com/watch?v=nb_suK_4C5c

And after fitting the 36T version

http://www.youtube.com/watch?v=WupVgTF8YTg

going out for a nice long jolly tomorrow and will post back any thoughts.

I've been looking at these too, weight saving also?

only 10 grams, so imperceivable. but the quicker bite will be , I'm guessing.

Well a really noticeable faster engagement over what I did feel was an overly long 20 degree sweep before.
Quite happy with what I feel is a worthwhile upgrade. Great for 'batting' through wet thick mud when it's a requirement to have a leg dangling to prevent falling and kinda peddle a quarter turn with the other.
Nice deeper sound too.

did you need any fancy tools or was it pretty painless to do

It's incredibly easy, no tools required full stop.

Pull off freehub body with cassette on it, take out star ratchets, fit new ones. Under a minute, genuinely.

10g weight saving's not exactly bad as a by-produt, makes the 240s closer to the 190s (until you fit the new ratchets to those!).

No specialist tools. Remove cassette, put largest cog back on with lock ring then pull firmly. Jobs a good'un.

cool thanks will prob stick these in when my current ones go. Cheers

I don't remove the cassette, much easier.