I have a pair of these for my very clipper phobic horse. They are relatively quiet and the battery pack makes it much easier to clip a nervous horse without having to worry about them treading on the flex. The battery pack lasted more than enough time for me to do a blanket clip last year - they probably last longer than that as they showed no sign of running out of charge when I'd finished. On the down side I think I can get a better finish with my old noisy mains operated Heinigers - I found it much harder to do the lines for some reason and they ended up a bit wonky!
I actually bought these clippers on sunday for my daughters pony who is very nervous to clip, so monday evening we did a small bib clip, then my friend did a blanket clip on hers and another friend did a chaser on her pony, the clippers battery lasted really well, they are nice and light and not very noisy, ideal if you havnt got many to clip or a nervous horse/pony.
funny enough it took me a few goes to finally get straight lines, would def say they not quite as good as normal heavy type clippers but for what i want to do they were fine.