Well, Yuasa only makes and sells one Yuasa branded YTZ14S and it has 230 cold cranking amps. They don't make different models with the same type construction and amp hours and CCA. They used to sell a house brand under the Motocross brand that was supposedly of slightly inferior quality at a lower price. Batteries Plus used to sell them and still might. They were about $90 when a OEM was $150.
I believe the difference in battery life is how a factory activated battery was stored prior to sale and then by the bike owner. All unused batteries self-discharge over time and if the battery sits around a while in a partially discharged state the plates sulphate and capacity is lost, even in a 'brand new' battery. I worked for a while as a parts manager in a busy dealership and we carried a few mid-price aftermarket batteries of all common applications and usually only one genuine OEM application because you stocked what sold or the parts guys could sell. The counter talk went "I need a battery for my CBxxxx, can you help me?" "We have the recommended high quality $150 OEM battery with a two year warranty and a $90 replacement battery with a 1 year warranty, which would you like?" Most buyers went with a lower priced battery during my tenure so we stocked those in number. ST riders tend to be different from cruiser and sport bike riders and might ask for OEM despite the price. But then we didn't see too many ST owners in my store. Exide delivered Honda batteries to me usually the next day so if we sold the only OEM one we had it wasn't likely to sell another one in a day or so, one unit on the shelf was all we needed. Other Hondas take the YTZ14S so we kept one or two of those in stock
I bought one of those Honda generator batteries you speak of when they were available on the forum for $50. I think I got the usual 3 years I got on ST batteries, no matter the brand or cost. The less expensive ones online usually have 190 CCA if the specs are even available. The only one I remember that I would not recommend is the Motobatt battery. They have a unique variable terminal configuration that allows the cables to bolt down both horizontally or vertically but in the ST I couldn't get a socket or screwdriver to tighten the nuts while keeping the bolt from turning.