Thanks for everyone's opinions. This has been really useful.
Seems like my ipad could just be that much better if it had 10" rather than 8". I'm leaning towards the 10" Boox. If I get a 10" I think only I'd use that. I'd like to think that if I had a 12" I could use that to teach with instead of needing to print PDFs off quite so much but it's hard to say. So I'm tempted to stick it out for as long as possible until the 12" devices come right down in price.
Chinese 10" carta
now available for $220 but I think the Onyx is probably the safest bet - because of the the software and I really appreciate that insight thanks Pajamaman and everyone