With regard to exporting, deckbox can export your sets in csv format. I think if the other guys support any kind of import, you could get the csv to look like their format by changing it in google spreadsheets or something of that sort.
Tried with Excel, it takes many steps, some not very user-friendly and the file succeeded in getting about 67% of my collection there, the reste being sucked in the void... I'm still trying to figure out an easy way to do it, but some cards are not spelled the same way. Nevertheless, thank you for adding Crown!
We'll import the missing ones after the weekend.