Need another new battery-suggestions?

Hi Guys,
we recently got a 2005 4×4 660. I really like it.
The battery that came with it was old. I bought a
YTX20L-BS Sealed Maintenace Free Battery High Performance 12V SMF OEM Replacement Maintenance Free Powersport Motorcycle ATV Scooter Snowmobile KMG

off amazon for $60 in August. Didn’t start using it till September and in December it was slow to start (Atlanta was 65 degree temperatures, so it wasn’t from being too cold and losing a charge).

our mechanic said the battery was crap when we took "Blue" in for some service.

The stupid battery was dead dead dead. we charged it, got Blue started 2-3 times yesterday and late in the day battery was dead again.

The Kapsco Moto.reseller on amazon said their warrantee/core charge is only good for 30 days – at least I’m not stuck with buying another cruddy battery from them.

Anyway, what batteries do you guys recommend, and where might I purchase?

Many Thanks!
~Lisa