355F1
The F1 is a fine enough machine, getting a little old these days you may find payload limiting if you require much fuel. New machines are noticeably quicker. Do you like Allison engines, I have no problems with them but many hate them. I have not flown the F2 but don't believe it is much better.
Not enough money for the N or newer gear?
PS. Newer machines versus Allison engine machines..is it just me or are there a worrying number of 135 engine incidents?