I picked one up last week. Managed to charge nimhs and my first lipo, and also set up a charge / discharge cycle over the weekend. Great piece of kit, but you're right - the instructions aren't great. I had to constantly google for details...found this thread nice and helpful
http://www.msuk-forum.co.uk/topic/144582-core-uac-50-charger-questions/
I use either the HPI battery mentioned above, or some no-brand 4600mah I've had for a while. I get up to about 30mins I think...I'm keen to see how much difference cycling my older batteries will have as I've never done it before.