In reply to CurlyStevo:
I cant compare to the tikka XP because i don't own one but I get about 4 weekends in winter out of my Myo on bog standard Duracell's.
_
Story.
Climbing a route in Cali and we had fixed the first four pitches with three lines 2x 50 m 10 mm and one 8 mm section to reach the floor and pizza/beer/ego massage.
My partner headed down and left me with the bag to finish sorting out stuff. It was getting dark so I grabbed my Myo off the back of my harness and in the process tore the cable out of the lamp rendering the unit usless - gotta love sky hooks. We hadn't hauled our spare gear (only water and hardware) so there was no spare lamp.
At this time of year it gets dark (really dark) fast! I could see to attached myself onto the first of the lines with my gr gri and using what little of the natural light was left sorted my harness so knew where everything I was going to need was - away I went.
50m later I reached the first knot and began passing it, thankfully I could still see - just - and it just took a wee bit longer than normal. I was helped by the two bolt belay which reassured me that everything was working before I disconnected from it.
an further 50m later I reached the next knot. a triple fisherman's 8 mm on 10 mm and by now it was very very dark. I knew that I was about 30 m from the ground but I couldn't see it.
I very carefully backed myself up on the 10 mm line above me with both my ascenders and moved the Gri Gri onto a 8mm line!!!! I then had to get my weight onto it but because it was dark I had over reached with the ascenders and the gri gri wanst holding on the 8mm tag line. A lot of swearing and down jumaring and wrapping things round legs and prussic loops later (about 30 min) I was on the ground more than a little scared. Colin the appeared out of the trees wondering where I was.
it dosn't take an hour to rappel ~ 140 m of fixed line unless its dark and you are very scared that you have screwed up toy system. So much for check then check again - more like feel around like a plonker until you are reasonably sure that its rigged correctly.