Im thinking along the same lines with these 3 buggies..........before i jump ship from my SX3 am gonna spend a bit time with it and give it a chance as im not really getting a feel for it.
Ive also got a B44 with a load of spares which will be cheaper if i move to the newer B44.2 as i still really like it and takes very little to setup.
Most people at our club now have the K1 which does look good and seems to go well, round our indoor track which will help more with spares, setups and tips.
As for the XB4, i drove my mates car on sunday and got used to it straight away and could push it hard if i had more time with it and i know how strong it is as ive seen it in a few hard crashes and still survive.
Hmmm choices, choices