I'll second the multiverse versitiles. Although I don't own any, I do own several kits from multiverse gaming and they are probably the best kits I own.
A quick run down of my experience with the different mdf terrain makers whose products I own...
Multiverse gaming
Very nice kits indeed, all except the magnatowers have accessible interior floors, though these are undetailed. Kits make extensive use of white board (thick card) to add some depth to the texture and hide any unsightly joints & pegs.
Probably my favourite manufacturer so far, only real issue i have with them is the lack of holes in floors for stairwells.
Sarrissa precision
The city block range is nice if a little too uniform and doesn't use card as multiverse does. Though their gas lamp alley line does. Also their more recent kits in the retro America & retail lines have both card detailing and interior detail Inc rooms.
All in all a very nice range that keeps getting better with each release.
Again though, has the same problem as multiverse in the no holes for stairs issue.
Tt combat
Definitely the cheapest option, so if you're building a table on a budget, then look no further. Most of the range (barring some of their larger kits) have accessible interiors and most have cutaways for staircases (which they also sell) though it's only there more recent kits that make use of card for texture depth.
Also worthy of note here is they have started producing resin litter and furniture, that I can't recommend enough, regardless of which brand's you use for buildings.
Sally 4th
The terra Blocks range is great for making modular interiors from and they offer a great range of interior & street furniture to kit your buildings/streets out with. I'm currently putting together a urban blocks mall (minus the base board intended for zombicide) to use on my zpoc board and am really impressed with the kit...
Just wish they'd release a corner section so I could vary up the layout.
One thing that has really impressed me with the range is the colour print outs they come with (such as snack racks for inside their vending machines) and glazed windows, must for any big store fronts.
Not had a chance to work with any knights of dice or 4ground kits yet but i know KoDs sentry city and 4grounds gothic city are just outer (all be it very sexy) shell.
Hope this helps, i can rant about mdf terrain all day
