I just picked up an REI Powerflyte Half-Zip hoody from the clearance rack.  Can anyone compare this with other tops like this?  I've never owned an R1 or T2 hoodie, but would love to know if this is comparable. 

It weighs ~11.7 oz in medium and it has Polartec Power Dry side panels. 

I think I have the equivalent hoody version, can't compare it to an R1 but it is my favorite all around active layer, use it for winter trail running, snowboarding under jacket, mountain biking, and it will become a shoulder season piece for backpacking.  The material seems to have the right balance of wind resistance, heat retention, and moisture transport for me with a thin short sleeve t-shirt under it (cap 1).  Too bad they don't make it anymore.