Occasionally a Uretek coating will wear out kinda fast, but usually they last quite a long time. My ski jacket has seen hundreds of days on the ski hill and it's got all Uretek zips and they're all looking good still. It might have something to do with how tight the slider is? I have seen one or two over the years that has worn out prematurely but I wouldn't say this is normally the case.
You're right about the non-uretek ones being easier to open. The best zippers are actually the toothed, waterproof zips like the YKK Aquaseal Zip and the RiRi zippers. These are waterproof, last forever and open easily like a normal zip. The downside is that they only come in bigger sizes (ie. #5) but that may be what you're using anyways. It would add cost, but these waterproof, toothed zippers are the best.