I find my Urban 550 to be adequate for dark trails, but running it on high only gets 1.5 hours at the most between charges, so I actually wouldn't mind something a little more powerful whose "medium" setting was in the 500-600 range and I could get by without charging every day.

That Expilion 700 seems like a good deal, but I've heard the mount sucks (like most Cygolite mounts do).