I second the praise of LR31A - nice aircraft, though the only jet I have flown :-) Small cockpit, even smaller baggage space, toilet is only for "emergencies", but then, it only flies 3 hours maximum anyway.
There are some for sale, ex Flexjet, I think around USD 4M a piece.
I would say the 31A is a good deal for a corporate operator who has a limit to spendings on a jet.
TD