What are they and why did I buy them?
In theory, these were good purchases. You got two double-side poster battlemats and a short 16 page adventure booklet for $15.
They came out around 2005/2006, at the height of D&D 3.5e. At that time, I scrambling for any sort of accessory to make that D&D 3.5e easier to game master. So most of these maps–especially those from Fields of Ruin, The Frost Fell Rift, and City of Peril–made it to the tabletop.
The adventures which came with them were nothing memorable, though I remember using an encounter or two.
Fields of Ruin had a nice ruined castle in it. A ranger in my campaign met his demise when a Frost Giant stepped out of a tower in The Frost Fell Rift. Also, the Caves of Chaos battlemat in The Frost Fell Rift made a good orc lair when the PCs decided they needed a few more experience points before continuing on their main quest.
Why did I sell them?
While the battlemats were fantastic to look at, realistically you can only use them once in a campaign. Some of the locations are too specific and never saw use, like Hellspike Prison. None of my campaigns ever called for a keep surrounded by hellfire and magma.
Also, I needed some cash, so they went up on Ebay.
Sometimes I wish I still had the battlemats from Fields of Ruin and The Frostfell Rift, but if I really want them again I’ll get them. I don’t miss them that much. And I don’t miss the others at all.
You can see better pictures of the battlemats at DM David.