I have 1.2 2013 Tarahumara boas. The biggest issue is ensuring you have pure stock if you want a boa that's guaranteed to stay small. There's been some outcross breeding done with morph BCI's, so make sure of what you're buying.
As babies they were all very defensive and stayed so much longer than their larger counterparts. I believe that this is because, being a dwarf species, they remain small and thus are prey for a longer period in their lives. Even now, as adults, if I startle them or touch them unexpectedly I can be met with at least a "nose bump" if not teeth, though once in-hand they are fine to handle.
Husbandry is just like any other boa, except they eat smaller feeders. It's hard to look at them and think they're not still growing. For instance, my morph/common adult BCI's get either an XL rat or 10-12 oz rabbit once a month, while the Tarahumaras get either a large-ish small rat or a small-ish medium rat or a 3-4 oz fuzzy rabbit.
My females are in 41-qt tubs in a rack, the male rattles around in a 34-qt tub. He's only 3.5' long, while the females are around 4.5'. Once these guys are past their baby nippiness they're great pets for people who live in apartments or condos, and who want to keep BCI, but who don't have the space available for 48" enclosures.
Eating: the females aren't picky and would eat themselves obese if I let them. The male went off food last winter and did again this winter, he obviously wants a girlfriend. He gets to wait until next season though.