Flat-barred bikes have seen a big resurgence of late, but bar ends are still rarely specced, despite the obvious advantage of an alternative hand position that better utilises the larger muscles in the upper arm, which is great for climbing. At 116g, these full carbon offerings from Profile are light and good looking. They're ergonomically shaped and excellent when gripped fully on the bar end. If you hold the clamp (as I often do when climbing out of the saddle) they're not quite as comfy, but they're fine if you're wearing mitts.
Comfort will depend to an extent on your hand size, so try before you buy. The clamp is carbon, which doesn't grip as well as aluminium, but the threaded alu insert means you won't destroy the moulding when you tighten it. Don't over-tighten or you'll pull the insert out, like I did - not ideal! Forty quid isn't cheap, but there aren't many ergonomic alternatives out there. If you don't want carbon, Cane Creek's Ergo Control grips are a good choice.