I used to be a loyal EMS shopper who believed that there was no real reason to pay up for brand names. But after purchasing the R4, I realized that there is no generic equivalent for any Patagonia product. Like other reviewers, I feel comfortable wearing the R4 over a T-shirt in 30F weather, and feel downright toasty wearing it over a Patagonia Capilene base layer. I love that the jacket is so snug: it blocks the wind and provides for ultimate moveability when backpacking. My only gripe is that the high pile of the fleece traps a lot of dirt and grit; a simple monthly wash solves this however. Pay up for the R4, or get a deal on it during the off season from a site like this, because its worth every penny.