Performance wise I wouldn't expect you'd notice much between a revup and non revup, ..although the revup does rev higher by a couple of hundred rpm. I have heard though that they can drink the oil sometimes which is why I was more than happy getting my non-revup.
What ever Zed you go for though make sure it has a good service history and it's important to run these car's on Super unleaded.
Have you had a look on the For Sale section here? Lot's of decent cars in there and there is also a trader on here called Tradelink who have a good reputation amongst a lot of Zed owners who have bought from them.