I had a AGM from Batteries Plus which ran fine for about 1 1/2 years until I used it in the parts bike to check out the engine.
I was cranking it quite a bit and had the charger on it set for 10 amps, 6-7 amps were going in. From what I understand about AGM's that amperage is OK, even 10 amps is OK.
I felt the battery case which was slightly warm so I figgered it was OK but at one point it suddenly died.
I thought maybe a loose connection somewhere but it turned out the battery shorted and went down to 7 volts.
I then picked up a Oddysey after hearing how great they are.
Been 6-8 months running fine, I haven't used it under those same circumstances so who knows.
Time will tell if it lasts any longer than a regular wet cell.
Oh, the battery from Batteries Plus was called a Xtreme.
I don't think I was abusing it and it should have held up to what I was doing with it.
Just as an FYI, "Gel" and "AGM" are very different animals.
You wouldn't want a Gel for a bike or car. Those are the types used like in emergency lighting and such designed more for a slow discharge. AGM's are better suited for cranking amps.
IIRC, Gel's need a special charge rate also.