After a week or so with FotM existence my opinion is:
It has it's upsides and downsides, but it ends up being somewhat of an annoying experience, it splits the community into a lvl progression that once most of the server climbs up its annoyingly difficult to find low level FotM's, so once you have a party you're pretty much married to that party progression and do it as fast as you can in order to reach the server FotM level. A-net did make beautiful designed dungeons, but the way it works it's just annoying. That added to the fact that LFG doesn't exist at all, you rely on using gw2lfg.com, which itself is still flawed, separating NA with EU players makes progression even more difficult and annoying.
Encounters like the last dredge boss and the swamp one can be extremely annoying without good communication, getting to be endless and up to a certain point boring, but that's a PUG issue. Other than that, the dungeons itself are fun and have some interesting mechanics