Well i gotta say rct 2. My reason for this is that more people own it, and i would be able to take part in a contest that i might actually stand a chance in, instead of the NL contests.
Far more people own RCT2 anyway, meaning you'd get a much bigger and higher standard turnout, imo.
Yeah, the scenery thing is a very big deal. From what i've seen, RCT3 is lacking. Also, the poor guy who had to judge an RCT3 contest would have to do so with possibly the worst frame rates ever, what with the processor-hogging requirements of viewing a full park.
On this moment I'm working on a rct-3 Match-up contest,but before'I'll put it online I have to know if enough men wants to join.The Missions are quite simple but you'll have to think very creative(or big).