2 strokes are easier and cheaper to work on if they go wrong. Also a well driven 2 stroke will beat a 4 stroke of double the cc.

4 strokes do sound the dogs bollocks though and have the advantage of being easier to ride due to their progressive power and better traction with the way the power is delivered.

My mate is going 4 stroke when we sell our RM 250 but im sticking with a 2 stroke.

Also 2 strokes wont need regular rebuilds if they arnt driven flat out everywhere, which you wont be on a track unless your shit hot but might be if your just straight lining it round a field. Even if they do need a rebuild you can get rebuild kits cheap enough and do it yourself.

Id go 2 stroke if its track action and bit of field. But four stroke if its road legal and going to be flat out everywhere