I tend to agree the OP; in general I prefer general Y on AC to E+ on UA (although there are exceptions).

When I last purchased E+ on a UA flight, it turned out to be an exit row where the seat didn't recline. While I had tons of legroom the seat was uncomfortable and I couldn't adjust it.

I much prefer AC's hard product (especially with AVOD, etc.) to UA's within NA (I've never flown UA int'l) and I find AC's soft product to be better too. Same goes to comparing AC to US and DL. I've never flown CO so can't make that comparison.