http://tech.yahoo.com/blogs/raskin/10631/will-the-best-battery-please-stand-up
saw it on yahoo news
These look very nice with 1000 ma output that more than fits MT deck requirements for charging and running the deck, and cost is reasonable.
Warranty seems generous at 2 years which hopefully covers less than 100% good batteries. However, estimated life of internal lithium is exactly 2-3 years whether used or stored, so figure replacement of internal battery or buying a new supply about that time.