What are the advantages/disadvantages to having a sealed or unsealed motorcycle battery?

The first thought that came to mind is water. being a bike and low to the ground, it would seem that a waterproof battery would definetely be the best choice, since road water could possible shorten out an unsealed battery. does this make sense?

2nd Answer. maybe, the unsealed batteries are also used for starting riding mowers?

A sealed battery will not leak if tipped over, but you cannot add electrolyte to the cells.

Sealed will not leak if tipped, but cost more. If you get an AGM type (Absorbent Glass Mat) they will be 15% smaller/lighter for the same energy storage and delivery but cost about 30–40% more.
I always go with sealed. I figure the extra cost is like insurance. If I ever dump my bike, at least I won’t have to worry about acid damaging things.
Let the good times roll.

I didn’t think that they were sealed in case the bike was dumped, (b/c let’s face it, if it does turn over, I think I’d have alot more to worry about the battery/bay.

I thought that b/c the battery is constantly turning on its axis alot more b/c of the great degree of leaning when riding through turns.

I like what @john65pennington said regarding unsealed batteries. . . they aren’t just for motorcycles, and unsealed can be used in different applications.

Sealed batteries are made to be replaced instead of repaired like almost every other automotive parts are these days. Sure there are advantages like not leaking under extreme conditions but if you’re not an extreme rider then it’s not really an advantage. If you work on your own bike then you might want to opt for an unsealed battery. If your more the type that always takes it to a mechanic or just sells it when there’s something wrong then go for the sealed one.

Thanks everyone- great input.