WE operate some lear 20 series airplanes.
Maintenance is not very expensive, offcourse if you take on a renomated company to do it for you it will cost you. A lot cheaper and easier to hire a US mechanic that worked on them and keep them on the payroll
European ops won't be easy, as you really need to get to the FL400's as fast as possible, and the plane wouldn't like delays too much...then again, I just flew Los Angeles to New York with just one fuelstop, so the range is pretty decent.
cheap planes>> pick one up for around $200.000,- and that makes you ready to fly!! You can buy a bunch of fuel for 2 million bucks
RVSM will be an issue, but expect something to come up for it, there are quite a few 20-series out there and there's no way they will just ALL go out of business. I just don't see this happen.
As far as difficulty flying the plane, yes it's high performance and it will bite you in the behind faster than anything, but it ain't rocketscience either. We fly them with low time pilots, I had 1200TT when I became a captain and my co-pilot had 0 jettime and just got his commercial license.
Insurance for us is dirt cheap, so I have no idea why everybody else is so negative. The only thing why we don't really make a lot of money is that the plane is small...a lear25 goes a little better in the marketing, and our maintenance scheduling is So bad that our planes are down almost 50% of the time because our mechanics don't walk very fast........