I have a Bear Hug Baby ring sling, it's just fabric, no padding, and it seems to do fine. Once we got the hang of it Jazz didn't seem uncomfortable, in fact it wasone of theonly places she'd sleep some (a lot of...) days.
For me it was comfy enough, BUT look for one with a wide shoulder. Narrow shoulder straps will dig in or ride up into your neck. If you have it spread out enough you don't need padding.

I think most ring slings do, but it's good to be able to tighten the top and bottom rails independantly (I think the issue is only with the 'clip' slings, not the 'ring' slings but I'm not sure so I just thought I'd put that in).

Hopefully someone who has tried a few will come in. I love my ring sling (used it from newborn and still using it at 18 months when Jazz is on my hip!) so never bought anything else hehe.