Well, guess the horse just has a little life left in him, LOL. Yes, we’ve had those discussions and many of us have traveled that road, plenty folks use side valves.
In my winemaking situation, if I had a large steel fermentation tank, that would make plenty of sense. Unless you ferment on tables, a logistic I cannot accommodate with 7+ fifty gallon fermenters every year, they’re floor bound. So by the time the first carboy‘s wine level rises up to the dropping level of the wine, the gravity flow stops and the AIO has to finish the job. Then there’s the valve assembly. I know, yours hasn’t leaked in 47 years, when I used the side valve assembly, they get bumped, kicked, and there were leaks unless you went out and got the high $ stuff, and they’d still clog when the cap got down to the valve with plenty wine left. Then I began searching for the right filter to put on the valves, the high $ stainless steel ones rock, if you only need 1. Then you can’t stack your fermenters for storage without removing all of the valves, that’s yet another step to start and stop every season.
The beauty of our hobby is the freedom we all get to choose, after trying lotsa stuff, I chose to add a $5 piece of pipe and a few hours labor to my toolbox, and it‘s been a welcome addition.