I've had a Motobatt I bought from Wemoto on the Fazer for a couple of years now, with no problems at all.
It's been through a couple of winters, powering the bike and Gerbing heated gloves, and has been left, at most, for about a month without use, but always turns the bike over.
The Yuasa I had before, on the other hand, only lasted a couple of years and was pretty poor at holding a charge, especially in the winter, so I'm quite happy with the Motobatt.
I'm not convinced that trickle charging is necessary, or that good, for batteries if the bike is used regularly, even once a week or so. You wouldn't expect to do it to a car battery, after all (well, I wouldn't!)