from what I have heard (anecdotal only!) the avics, and T blondi seem to have the most problems for people.
I have had 1 A avic die from a bad molt, and it's the only T I've had die from one...so I don't know...
I now have 4 A versicolors, and they make me really nervous! My two tiny babies just molted again, and seem to be doing wonderfully. The juvies that I have also seem ok...but I just got them a couple weeks ago.
I would feel totally unprepared for T blondi!
I have to agree with the post about the avics, at least the versicolors. I have one spiderling that has given me nothing but trouble with molting - lost a leg 2 molts back, got it back, then lost it again this last molt. Another from the same batch, however, hasn't had any problems.
I have heard that curly hairs can develope a scab-like spot on their lower abdomens that will rupture during a molt and kill the spider - this from the Tarantula Keepers Guide - but I haven't seen this in any of my specimens at this point.
Ooh now you're kinda making me nervous :8o I have a 2.5" a.avic, a .75" a. avic sling, and a .75" a. versi sling. I really hope they don't have too much trouble. I've been very careful to keep the moisture up so that they have as little trouble as possible. I'm sure in future posts you'll find out if I had good molts or not
Just to play devil's advocate: I've never had any problems with Avicularia sp. molts, or with my Theraphosia blondi (which was 1" when I got her, and 7" now!). That said, I keep the humidity for each around 90%. It helps to have a gauge in each enclosure.