Have an 08 290 with Cab head, Keihin & Boysens.
Map 1 is normal. Map2 is slightly retarded. I've noticed on big straight shaley gravel hillclimbs 4th gear nearly wide open on map2 wont lift the front as much as map 1 so you can keep the throttle on. You dont want to back off in 4th.
Bike has big smooth even power but map2 would definitely help in the wet. Map1 most of the time.
There's an 08 bike test on tmxnews.co.uk thats worth a look.
Just in case anyone is interested, carb jetting differences between my old 2000 & 2008 were pilot-42, neadle clip 2nd from bottom, main 120 on the 2000 and pilot-35, neadle clip 2nd from bottom, main 120 on the 2008 with the same Keihin.
Dellorto carb also showed big differences on the pilot with 38 on 2000 and 33 on 2008.
This is at sea level in Australia. This just shows that all bikes can be quite different.