psychoanima: thanks for answering.
Well, ToonzPremium are commercial software, and as such, I suppose you can get more support if things dont work. Like I can still not use open Toonz on my MAC because of the zoom-issue with wacoms, but if some programmers resolve that, Opentoonz are almost perfect.
Digital Video write on their site that they will "including the most interesting and powerfull OpenToonz features." and keep the two versions compatible.