I don't have a real preference, but I do get different sensations in the tight-loose spectrum.
When it is super tight, it feels great, however, being uncut, it means that she'll grip my foreskin and I get this feeling I'm just gliding along my foreskin unless I'm doing full strokes. I do love that feeling of really stretching out a tight pussy though, that'll never get old, but with a tight one I feel like it's fighting me the entire way, trying to push my cock back into me. Not a bad thing, but increased pressure makes fucking a chore not to blow early.
With loose, sloppy pussy, you can really go to town. It's just accommodating and there's no drama. You just get completely enveloped and there is a sense of intimacy in that I can't easily find the words for. Also, the build up to orgasm with gentle pressure makes you appreciate the subtle verberations and movements she makes. With a tight one, you have almost strangling pressure throughout, which sometimes, makes it difficult to relax. I just find the build up is better when there is gentle, almost teasing, pressure on my cock.
If I really had to chose, I'd go for a loose yet muscular pussy. One that has no problem absorbing you in your entirety but can really bite down when she wills it.