Don't wear them while running but do wear them when climbing. I find the fit is 'snug' but can't fault the quality or the service. I have/wear both the T shirt and the long johns and they work really well in keeping the sweat away and seem to keep me warm without overheating, so I generally feel very comfortable without that 'wet and clinging thermal' feel.
Like Big Fella says tho, I feel like I've gone full circle from string vests and lambswool pullovers to Brynge vests and Merino wool thermals