I've found in the past that the wet style batteries do seem to last longer or are servicable at least. I leave the bikes for weeks on end(work) - sometimes taking the batteries out to tender - but generally they get abused and repeatedly the wet cells, (with me regularly as possible topping them up), they seem to get the cranking amps to the starter motor for longer where as the sealed variety tend, in my experience to falter somewhat sooner by loosing an ability to hold a charge - with batteries of similar age. There could be many reasons for this, I tend to find that the wet type batteries are better suited to my Bike lifestyle/pattern - so far! I'm running a sealed Yuasa on the S3 presently, as I've done before but there will come a time when the wet cell from the Spripple will inevitably take over starting duties, as has happened before - but left to my own devices I find the sealed ones generally trouble free for their duration - 2+ish yrs as opposed to perhaps 21/2 for the wetuns. Living in LA., temperature is rarely an issue so I won't comment there - but them sealed jobbies are sure easy to maintain.
http://www.yuasabatteries.com/batteries.asp This article is very positive in it's pitch - but my experience has me holding a slightly different perspective, or my reality has been a little extreme for normal battery working perameters, or strangely lucky - confabulatory even!

If you get more than 2 trouble free years from a battery of any kind - all is good, basically! Keeping 2 bikes in working order is simplified by having one maintenance free battery, halves the duties! Nothing is really simple.