Fat Cats at armthorpe, its a good track, hardpack and has some huge tabletops. they had an enduro there last year which was pretty cool. Well just make sure you ride both and you'll know what you want!
well i mean i don't do rebuilds and valves myself my mech does it but he reckons they are harder to rebuild when they do go but you'd have to ride them really hard to do it quickly, 40 hours is a long time, i've only ever had two that have blown up and they had both done beach races. Ultimately anyway unless your really technical you wouldn't be able to do a full rebuild on two stroke yourself anyway, a new piston and rings maybe but a new head not. Go for the four strokes they are the way forward but if you really like 2 strokes, which i still recomend you try them just incase, then get one of them its just a 250f is just such a hassle free bike. Which track do you ride at anyway?