In my experience, they're all poor quality, at least as far as the quality of the Terry towelling and the sizing and fit go. I've even got some old ones which used a poly-cotton blend ( not comfy).
Because they are quite costly from retailers, you may want to think about making your own. Doing so probably won't work out cheaper, but at least you'll be able to choose the best, or your preferred, materials.
Something else to consider is Terry towelling pants without an outer plastic cover ( you wear plastic pants separately, over them).
Drying time is the main reason, but it'd also allow for a greater choice of plastic pant style.