As a Dungeon Master, I have a love / hate relationship with Dungeon Tiles. I love the simple fun they add to an encounter, and the detailed artwork inspires encounter design. I love how my players interact with the artwork, and I love the nice clean surface they provide. There are no odd curls for miniatures to get stuck on, and they typically make it very clear which squares can be occupied and which are blocked.
I hate preparing dungeon tiles. It starts with a box of randomly disorganized tiles which I have to fidget with until I put together something suitable for the encounter I have in mind. Often this leads to some mix and matching (which I also dislike). I try to minimize mixing dungeony tiles with village or foresty tiles, because that just looks janky, and if you’re using dungeon tiles, it shouldn’t look janky.
When possible, I try to have the tiles laid out prior to the session; I then cover them with a wet erase map to preserve the surprise. That works pretty well, but sometimes I have to move the tiles in when an encounter begins, or else build the encounter anew, in the moment. Either way, there is a disruption of play that I don’t love.
Later in my 4th edition campaign I started using poster maps more often (following Michael Shea’s advice from Sly Flourish.), and I always had my trusty wet erase map at hand. When I had a specific vision for an encounter, I found the wet erase map, sometimes combined with tiles, to be the best tool.