Thought I might get my BN some caves as the pepps and common's are getting on for age and size.

Seems I can get slate caves and terra cotta caves and PVC caves and combination PVC/Slate caves. There are rectangular caves, round caves and D-shaped caves. Then there are straight and tapered caves. I never knew BN were so spoilt for accommodation options.

Is one type better than others, and if so, why?