Not endorsed on them, however could comment with a little bit of knowledge.
Operating altitudes typically in the FL160-290 range. Depending on the engines, as a lot of the later ones, and a few of the old one's have the Raizbeck mods, which gives more performance from the engines. I think the 'useful' ceiling is around the FL310 mark. Pretty sure the Pearl/Airmed B200's don't have Raizbeck though.
Airspeed on descent get's up to around the 210-240kt mark. Could probably even go beyond that if you pushed the torque up.
So they're a very good performer. One of the nicer light twin turbines you could fly.
morno