I've been using the evo7 arm warmers for a couple weeks and they're awesome. They're warm but very breathable, and I don't need to take them off until outside temps get into the mid-70s. I've had no issues with slippage. They stay in place without any uncomfortable pressure points. In short, they do what they are supposed to do and you pretty much forget you're wearing them.
Like these so much, I bought a second pair. They are great for the in between seasons. Not a winter or summer arm warmer, just warm enough to keep the chill out. No silicon, and they stay up! I have problems with silicon and get skin reactions from silicon. The Assos arm warmers are great, and no skin issues at all.