i use 110amp numax batteries in the hobby. i think they're about 50 quid each, which isn't a lot really.
i find that on a rally for a weekend i can pretty much use the battery as hard as i like and it can handle it. for a rally of more than 3 days i would take two.
the fact that you're not reliant on battery power is probably the worst thing for the battery. you should really discharge it every couple of months as leisure batteries are designed to cycle constantly.
to answer your question though, i find the numax as good as any.