Just thought I would add my bit of experience into the mix. I have been flying a P180 on and off for the last 3 years. I cant really fault it! Sure its a got a few little problems like any other aircraft but you cant beat it on perfomance with any other similar priced aircraft.
You cant really compare it to a B200 as it goes 100kts faster and the rest with a stand up cabin and full stand up washroom with noise levels that are quieter than most jets! You have to compare the Avanti with things like the Citation II's, Bravo's,CJ1,CJ2. I operated one on a AOC and after a lot of hard work we were doing 70 hours a month! We didnt even bother competing with B200's as we were taking people off citations and even Excels! Once the passenger flew in it there was no turning back!
You can get a good 2003 model with the increased weights that make it an Avanti II for $5.3. Now thats not bad for the performance you get (6 pax plus bags 1300-1500nm).
With regard to maintenance all you need to do is get an engineer to do you monthly checks and for the big ones send it to Dusseldorf.
Personnaly I would have one now and put it straight back into the UK charter market, but theres the small issue of my bank balance!
All the best