It still is free for members of officially recognised MB clubs. The only change was that Daimler shutdown the old EPC, and moved everyone to the Xentry system used by dealerships. However, WIS access was removed in the process, and we were told it ain't coming back.
The whole migration was a massive failure, they never anticipated the scale of club use.
It took months for people to regain access. Some still haven't, and it's been well over a year.
It's not much different than the old EPC, however has the big advantage of running natively in a web browser on any capable operating system.