I think the only feature that was initially intended that didn't get implemented is the calendar.
I use it all the time - it is by far the best, most flexible world building/campaign management tool I've seen (and I've been playing a LONG time
).
You buy the software once and can install it on as many machines as you wish and don't HAVE to pay any monthly fees just to use the program.
BUT, to sync your realms between machines (and to allow your players to sync to their machines if they've chosen to buy RW themselves) you do have to pay a small monthly server maintenance fee (well worth it, in my mind).