Climbing bars? That's not an immediately recognizable name for a bike part. Best I can come up with is that you're talking about BAR ENDS for a flat bar bike. IMO, there's not that much to talk about. The dirt cheap ones are available in steel, the majority is aluminium, a minority is thermoset plastic or Titanium. They can be straight or hooked at the end. The length can be different. There's one or two that'll extend both to the rear and to the front. Ergon makes them as part of the grips. Although I haven't looked, I assume they're available in carbon fibre as well. On my XC MTB I use a pair that's fairly long. When I hit a road section I scoot my grip way forward and get into some sort of semi-aero tuck. On my MTB-based commuter(one size bigger) I use some fairly short ones, just to get the option ofr a thumb-forward grip as well. 2nd best I can come up with is that you're talking about base bars for a TT/Tri bike, in which case I have even less to say. Weight and cost will differ, Some come with a bit of drop. They're available in different clamp diameters and width. Don't expect all bars to be compatible with all bar end shifters or bar-end mounted brakes. Quality-wise I wouldn't expect to notice any difference while riding.