I don't think the anecdotal point is overstated at all. I think the vast majority of DIYers would just plug n play anything that fit. Unless you know the charging systems were a match and the batts were cared for as the specific type requires, a handful of stories do not infer anything. Just about anything will work at first. Charge them incorrectly and they will die prematurely.
I can't even count how many batteries I have tested over the years. Top quality brands like Rolls, mid quality Trojan, Crown, Deka, Superior & US Battery & lower tier like JCI batteries. I have seen the most expensive batteries made die in under two years, I have seen the cheapest batteries last 9+.
The one common denominator for long battery life I see is proper care, owner understanding of the charging system and often a battery monitor and owner who understands how to use it.
I often find very sweet systems, that SHOULD result in long life that don't. Not because they can't, but because they are installed or set up incorrectly. The act of buying an expensive system to feed and maintain batteries does not stop at the installation. The set up is often the most critical aspect.
There certainly are varying levels of quality amongst battery brands, but also price. Then there are re-branded batteries that are identical that sell for double the price of the same battery elsewhere such as the WM/Sam's Club scenario. Paying double for a battery with a different sticker does not translate into double the life.
I see inexpensive 6V batteries, at half the cost of a "premium" outlast the premium battery quite often. At half the price that is quite a value in Ah's to $$$.
For 12V batteries in wet there are two series I really like (other than Rolls).
The US Battery 12V's such as the US31DCXC
This is a great quality group 31 130Ah battery at a very reasonable price.
The Trojan SCS series is also excellent but I don't feel the price premium over the US Battery line is worth it. For me the price difference is over $65.00 per battery. That's not chump change and the cycle life would need to be drastically different which I just don't find to be the case. The Trojan SCS batteries are very similar to the US Battery 12V DCXC line up in terms of quality level.
As a very slight step down I like the entire Deka/East Penn line but their 12V batts pack less Ah's than the US DCXC or the Trojan SCS batteries..
WM, Sam's Club, NAPA and others sell these Deka/East Penn marine batteries. The 230Ah 6V Deka's I'd put up against the Trojan T105's or US 2200's any day of the week. Crown's are also excellent 6V batteries..
Lots or reasonable choices out there and that's just wets. There are also AGM, TPPL AGM, GEL and Li technology batts...