I have a 4 battery charger from Battery Tender taking care of some automotive batteries and a 2 battery Pulse-Tech handling two motorcycles, plus a Pulse-Tech mounted in our Ford F350 7.3 litre diesel with dual batteries that runs off the 12 volt batteries themselves but is supposed to prevent sulphation of the battery plates. I try to fire up The Truck once a week to keep the batteries charged up.
I can't comment on which is 'better' but am satisfied that they are keeping the batteries alive over the storage months. Have a look at the economics, as I picked up a second Pulsetech parallel charger, and subsequently realized two items: I didn't have a real application for it; and (considering the price) I should've just planned on replacing the batteries a bit sooner that the desulphating feature might have required. And - please note! - this is NOT a criticism of Pulsetech!
Battery Tender seems to be a pretty standard maintenance charger in the shops around here for motorcycle batteries.
If anyone is aware of any compararison test between the various products - please share! Thanks, Doug