I had a really bad crash once cuz my bar end cought a branch and I supermaned OTB into some rocks. I cracked a couple of ribs which really sucks BTW.
For a typical mtn bike I use a riser bar and on my singlespeeds I use an On One Mary Bar. The swept back Mary offers a more natural hand position and greater leverage for climbing.

If you really want to try out bar ends, the best I've used are the Cane Creeks. I used these for a couple of years on a riser bar until I switched to the Mary.