Given your stipulations, I would choose the 390.
However, I think one thing about your original post makes me think buying new might not be wise. You said they weren't big on maintenance, air filter cleaning etc. If they crap up the filter or run it wrong and burn it up, what are the chances of getting to use the new saw warranty? Unless the dealer is a good understanding one and they have a good relationship with them then I would give the warranty consideration much less weight. If warranty was not a consideration but local parts and service availability was I would try for a used 361 or used 390, would save enough to probably get several loops of chain and a pair of chaps to share.
Good points. A used 361 would be perfect them...as far as performance goes...at least so I have read.... I've never ran one, only picked one up at a dealership. But I'd hate to see what it looks like after a few of their cutting seasons. They tend to only use one chain until it is very dull, and the air filter would be very dirty. They do seem careful about putting the right mix in the gas tank. I might would have to take on the responsibility of maintaining the saw...I'd hate to see such a nice saw not taken care of. I'll talk to one of the boys a little later this evening...if he's not out girlin'...
Kevin