My slightly biased view is to go with wd. If you change your station later you can still use wd on it. WD has lots more features than other software, so as your needs change you don't have to go and buy new software. Brian (Developer) frequents this forum, and there is support for it at weather-display.com. There are also many people here who use it. For the price it is and the feature set I don't think you can go wrong
I have used Cumulus - it is easy to set up, but going from wd to cumulus it seems somewhat feature restricted. That said I would have thought Cumulus would work with the WS2355?