The other day I posted a question on one of my favorite forums to get an idea on how people feel about bar ends. Most people were strongly against mainly because they are of the freeriding/hucking mindset who believe bar ends are really for hooking onto small sapplings as you ride down the trail. I would say somewhere in the neighborhood of 50% to 60% of all the 29ers that I have seen, especially the single speeds, all have bar ends.
I ordered a pair of Ritchey WCS bar ends from REI and they came yesterday. Quick to install. At first I was a little apprehensive about putting them on because they weren't the COMP style from Ritchey but then I remembered why I didn't get those - weight! These were 100 grams lighter and yet they still felt heavy. I guess they have to be in order to hold one's weight focused at this point.
Sort of tried them out by coasting a bit on the bike (still don't have pedals) and I can see how they will help climbing. Can't wait to try them out for real. Another week to go on the DL. I will post up a picture later.