I like em. The maps add a nice visual. As a rule, the encounters are loosely tied into one another, forming a sort of adventure. If you come into one looking for a solid adventure, you'll probably be somewhat disappointed.
With Frostfell Rift, they gave 2 encounters for each map rather than just one. Again its only a series of connected encounters rather than a whole adventure. The reason the ELs are all over the board on this one (in answer to NiTessine) is because a number of encounters are listed as something you would come back to later on in the campaign, as a way to get more mileage out of your maps. You're not necessarily supposed to go from one ancounter to the next to the next. It doesn't quite work that way. Thats why the ELs go from 4 to 17.
SPOILER
The whole thing is based on the PCs having campaign-long run ins with a Cult of Erythnul, starting with an encounter with Cultists in a Library (map 1). The PCs supposedly befriend the librarians and eventually find out about the cult. At this stage you could have them do something else, but be stalked by Cultists. Eventually the PCs get word from the librarians that the Cult has an ancient shrine in Hailstorm Tower. (map 2) PCS wreak havoc on Hailstorm tower. Then maybe the PCs do something else, until its discovered that Pilgrims on their way to the Library have disappeared. Reports point to the Skyfrost Mountains (map 3) where the PCs once again wreak havoc and recover the goods the pilgrims were bringing to the library. and so on and so on. It all seems to be aimed at having the Cult pop into your campaign as recurring villains.
End of spoiler
So, look at each encounter as the climax to a chapter in your "inspired by Frostfell Rift, but mostly homegrown" campaign.
Or, you could do what I do and just use the maps for whatever encounter I can dream up. Just remember that the main point of these products is the maps themselves.
In response to Merric: I agree wholeheartedly. Some of this stuff doesn't come up that often. I really wish they'd just do some more generic maps aimed a the RPG end. The strike against these maps for me is that because its also meant for DDM, too many of these maps have your DDM staple terrain: The magic circle, the blood rock etc etc. I'd really like to see just a generic forest, generic mountain, generic swamp, a campsite, a bridge over a creek, cemetery, crossroads...that kind of stuff.
But, its not that big a strike. I own all of these to products to date and plan on continuing to buy them.
ANd if you're not into maps and visuals, save your money.