Speaking from the point of view of over 3,200 hours on all three varients of the Astra "Classic" / Astra SP / SPX & G-100, (and over 2,000 hours in the SPX/G-100)all I can say is that it will probably give you the most bang for the buck of ANY of the midsize jets out there. I've made 18 oceanic crossings in them and I've never had any problems with Europe, but like G-100 said, I usually file northerly routes. Hawaii is doable, but you've got to watch the winds. The big gotchas are 02 - make sure you've got the long-range system installed or you'll be carrying some portable bottles in the cabin. The rafts and survival gear also go into the cabin so you're pretty much limited to 4 passenger seats. Finally, the extention tank takes up about 1/3 of the baggage compartment, but with some creative packing you can make it work out. All in all, the G-100 is a great compromise when it comes to real world flying. It's definately doesn't have the biggest cabin, but it's big enough most of the time. If you fly it by the book, it will make book figures day in and day out. You can plan on a normal cruise between 460 and 470 KTAS and direct climb to FL410 on all but the warmest days. I use M.76 for most of my long-range oceanic flying. Typical cruising altitudes are are between FL390 and FL430. FL450 is also a very usable altitude once you've burned off some fuel. You've got to watch the C.G. - they tend to go out the forward end of the envelope (even with the APU installed) when you top off the tanks and put more than 5 (sometimes 6) passengers in them.
As far as flying them is concerned, they've got straight forward systems - there aren't too many "gotchas". They're easy to get good landings with - if you watch your speed on final. They handle crosswinds well, but (for boosted ailerons) they're a bit heavy in roll and "typical jet" in pitch. If you're careful, you can operate them out of 4,000' runways, but don't plan on going very far. 5,000' is, of course, better and 6,000'+ runways won't offer you too many restrictions.
Lead Sled