My DS, almost 3, is very good with wees on the potty (although he has to be reminded / bribed constantly and does have accidents).
Our two big problems are
a) getting him to go on the toilet (he did it a few weeks ago at my parents, with the toilet seat adaptor, but back home refused again). The reason I am keen to do this is that I don't have to drag a potty round when out and about!
b) getting him to do poos on the toilet (or potty, if necessary - mainly not in his pants).
Any ideas? We had an epic tantrum today, when, after two wee accidents (they are rare these days and I know he can do better, so I got a bit annoyed), me and my husband tried to coax him onto the toilet. We won in the end, but, oh my god, it was an epic one! Think hostage negotiation situation....