I went through the type earlier this year. It's a very nice flying airplane, but the wet runway performance leaves a little to be desired. Try going transcon off of a wet 5000' runway with more than two or three pax...not going to happen. On the up side, it handles turbulence beautifully and is a very quiet ride. The pax seem to like it as well. If you have more than five or six pax though, it gets a little crowded in the back.

The ProLine 21 avionics are terrific. There are a few quirks (all Honeywell experience prior to the ProLine for me), but you get used to them quickly. Looking at your experience, I'm guessing that this will be your first type. Most people have difficulty with the avionics/FMS on a first type, but I feel that if you can navigate your way through any Garmin GPS product, then you shouldn't have many problems with the FMS. Repitition is the key.

Last I heard, FSI DFW was still the only training facility for the 150. The course was a little sketchy when I went through, but apparently, they've made great improvements since then. They should have it down to a science by now.

As for the insurance, I wouldn't be too concerned. As long as your student's company sends you for an SIC or full type rating (don't pay for it yourself), the insurance folks shouldn't give you any flack. Now, you're not going to make it as PIC, but SIC is a non-issue. Otherwise, jump on it. Sounds like a great opportunity. Good luck.