I like the full size 1911's but if I had to choose between one or the other I'd go with the Commander size. I have one of the full size Ruger SR 1911's (plus a Colt Gold Cup series 70), then I picked up the Ruger CMD and a few months ago got the Ruger lightweight CMD model. The lightweight is a sweet gun.
I'm very fond of the 1911's. For some reason the shorter barrel points better to me. I realize it's only 3/4" difference but I also like carrying the shorter Commander size better !