While I haven't owned one, as an Electrical Engineer these Xtreme Chargers are awesome, after spending an hour with a factory rep at a motorcycle shop.
the Xtremes don't just trickle charge, but induce a high frequency AC hertz signal to keep corrosion from building up on the plates.
Their technology is used my the military and state police to always have batteries kept in good order.
YMMV, IMHO, blah blah blah.
http://www.amazon.com/s/ref=bl_sr_automotive?ie=UTF8&field-brandtextbin=XTREME+CHARGE&node=15684181