Well, this post will probably throw a lot of "heat" my way, but, here goes. The original lead-acid battery (Yuasa) that came with my bike lasted 4 years and 10 months. My records reveal that that was after 44,286 miles.
The replacement battery (also lead-acid----Walmart) has so far lasted 2 full years and is still going strong at 53,708 miles. I merely check the electrolyte levels every 2500 miles or so and add water as, or if, needed.
Now, I don't have any problems with the maintenance free batteries, I'm sure that they are "the cat's meow", I just haven't seen the need to spend the extra money for one when I've been getting such excellent service from the conventional type.
After taking delivery of the bike, and experiencing the backfiring, hard hot starts, failure to start, etc., etc., etc., I found that the problem, on my bike, wasn't that the battery was no good, but simply that the charging system hadn't been properly grounded during assembly and therefore the battery wasn't being recharged while riding.
Once this issue was addressed and remedied, there have been no further battery problems.
'02 VN 750
stator replaced @ 50,570 miles
forks rebuilt @ 58,900 miles
currently on third battery & sixth set of tires