I recently bought some ASOS brand pants, but had to send them back and order a different size. The quality was satisfactory for the price on the pants, enough so that I thought it was worth the hassle of ordering again. Shipping is slow, though, compared to other retailers. Not too bothered by it, considering shipping and returns are free!
ETA: I used the size charts on the pants I purchased and even used a "compare" feature they have where you enter the measurements of a pair of pants you have and it shows how the item you're considering compares. Anyhow, based on this information, the pants I ordered were 1-2 sizes too big. The size I ordered was 1-2 sizes too large for me normally, so I figured ASOS must run small. I'm guessing things run more TTS, based on the fact I had to send for my NORMAL size. Does that make sense?