I’ve tried Zensah, UnderArmour, EMS, and some assorted others. I’ve used them in five applications: cycling, skiing, lacrosse, yoga, and at the gym. Here are my impressions:
Under Armour:
You can’t beat their compression shorts. They’re fantastic as a base at the gym, playing active sports (eg lacrosse) and when skiing. Wicking is excellent and compression is good. Sizing runs small-ish, but there’s enough stretch that it doesn’t matter much. In terms of tops, they tend to soak through and cool you down. This is either very nice, or very uncomfortaly damp. Thinnest material I’ve tried.
Zensah:
Super comfy stuff. It’s softer to the touch than UnderArmour, and exhibits less of the soak-through feeling of UnderArmour. Thicker material, but still nice and light. Compressive power is a little less, probably due to rather generic sizing. The arms on long-sleeve shirts seem a bit long and imprecise, although if you’re tall and lanky (say, over 6’) this would be a plus rather than an “eh” feature. FANTASTIC coupons available (30-50% off, just PM me). Haven’t tried it as a base for non-cycling cold weather activity yet, but very nice on the bike.
EMS:
I’ve got some older stuff from Eastern Mountain Sports. It’s fairly generic. Comfy, soft enough, feels like the same coolmax cloth as most manufacturers. It’s worn well for over 5 years. Nothing wrong with the basics!
Generics:
Generic stuff wears just like EMS, and feels more like UnderArmour than Zensah. Tends to be thin, exhibit soak-through qualities. As I said before, that’s great when it’s hot, not so great when it’s not.
When next I buy stuff, it’s going to be more Zensah, assuming it continues to wear as well as it has over the first few months. The only negatives I see are sizing, if it doesn’t fit you well (it fits me great, although it tends to ride up from the bottom at the gym. I’m 6’, 173 and wearing size S/M) and sleeve/arm warmer length. The arm warmers, by the way, are very light weight. Great for a day when you don’t quite want bare arms, or you’re warming up before a race/ride. Also good doubled up with long-sleeves for a little extra warmth and wicking. Made of the same material as the shirts.