I dislike WotC in general, but I love the dungeon tiles (at least the indoor ones). I have two sets of each, and I'm considering a third of each just for additional flexibility.
Personally, I don't like the Paizo tiles. They are really limited and don't mix/match well (one of the WotC tiles strengths). I've heard the later sets have addressed this, but I bought a few of the early sets and have never used them.
These are all PDF products/companies:
WWG Dungeon Tiles are good, but a little limited (they need to make more sets). You can also make tiles from a number of their other sets.
Fat Dragon makes tile sets. I don't have any of those, but I have some of their 3D sets. The artwork is okay - it looks more like photographs that have been digitally massaged to fill the volume.
Skeleton Key Games makes a wide variety of tile sets, and for pure range and flexibility, if you're going to print your own, you can't go wrong. The art is a little cartoonish compared to most of the other companies, too.
Ebbles Miniatures also has a set of SciFi tiles, I believe. (They're better known for their 3D vehicles/robots, and easily are the best out there in that range.)
For homemade tiles, I print them, then spray glue them to matboard (the kind of board that is used in picture framing) and then cut them out. This gives the tiles heft and keeps them from sliding around on the table or blowing away in an errant sneeze, and also makes them about the same width as the WotC tiles.