I bought the bike about 3 weeks ago and found it to have a decent low-mid range but flat on the top end.  Compared to a 2007 Ninja 250 I didn't feel as hard a pull and didn't seem to launce as well; even so the 0-60 time was almost the same and the GS has much better handling and top speed.  As a result, I decided to do a rejet and have found the following setting to work really well and give me the performance I was expecting when I upgraded.

Jets: 20/62.5/142.5
Washers: 1
Turns: 2
Float level: 6 mm below bowl seat with the bike level (i.e. bowl seat plane level in both axes).

The bike now has an amazing pull off the line and I can feel the fork springs unload when I roll on the throttle.  Power delivery is smooth across the RPM range at any throttle position with a nice throttle response.  After lowering the floats there is no trouble with low end richness and it'll accept WOT at any RPM.  The transition from closed to slightly open throttle is about as smooth as it was stock.

Now I'll just have to see what kind of range I get out of her.

Does anyone know how to get this added to the matrix on the rejetting wiki page? Or for that matter the Beergarage matrix (the add button gives a 404 error)?