540 cold cranking amps! That's almost double the Banner isn't it?!
That's what's on the spec sheet; certainly cranks the X-Wedge over at a fair old rate.
From what I could find on some bike forums the JMT batteries seem to get a good name, some other lithium batteries get slated and it sounds like there are a few out there that simply do not have the sort of built in circuitry that gives them a chance of working properly. Hopefully time will show that this one continues to just work!