I’ve chatted around a fair bit and the majority of avocado trees grown from grafts in my area are brogdens. Indeed they seem to produce well and I have seen several medium-large trees weather freezes down to 24 degrees without much damage. Definitely not the best tasting avo (and the seeds are huge) but more than tasty enough and cold hardy to keep around in 9b, particularly in the northern end of the zone. I’m also growing winter mexican and based on the first fruits from my small tree prefer them to brogden, as they’ve so far tasted quite similar to quality California hass, the latter of which I hold to my avocado taste standard.
I’d definitely be wary regarding the reputations of avocados grown in different zones/soils, let alone other states. There’s *a lot* of commercial cultivars grown and tested in FL 10b that I doubt would perform as well in 9b. Reed sounds really good in many ways, and I’m tempted to plant one for it’s cold hardiness alone, but cultivars can perform quite differently based on where they’re planted. Take the wurtz for example, which is a mediocre fruit in California but apparently tastes quite nice when grown in Florida. The opposite often occurs with a quality fruit from Cali grown in Florida. I would at least expect it to perform better in the slighter drier climate of 9b than in south Florida, but I’ve seen no reports of fruiting trees here.