Thanks for clarifying that, James.
In my case, I have so many different polypro shirts that they'd probably last me several life times! I have them in different weights (and weaves too - that changes their warmth) so I can pull something out that will be appropriate for nearly any hike/trip I can think of.
Personally - I don't think one is better than the other. Polypro met an unmet need when wool as a base layer wasn't an option for most, and now does it well and at a fraction of the cost of merino wool. It also takes lots of experience to learn how to hike/climb using the least amount of clothing necessary to keep you warm enough (and the operative word is "enough") so that you don't build up sweat which will quickly chill when you stop. Some days it seems you can spend as much time layering/de-laying as you do hiking.
Good luck with your search for a laying system which works for you and one you have faith in.
