Would you recommend these to someone who doesn't own a belt sander or other large surface sanding stuff?
Firstly, it has occurred to me that I may have just received a particularly poorly casted batch and someone else may make the same purchase and have very little sanding to do...now on to my answer to your question;
Short answer - Yes, on the proviso that you accepted that you may very well have to do a lot of sanding by hand on a flat surface/straight edge.
Long answer - The casted detail is great, and I can see that the models will lend themselves nicely to painting. The only real issue I have is the bottoms of the buildings are poorly done, they can be uneven and misshapen, which is the source of the sanding requirement.
You can achieve the same result with a few sheets of good sand paper, a flat table surface and a straight table edge as you can with the belt sander, but what might take 2-3 bursts of 10-15 seconds each on the belt sander per piece, might take you a good 20-30+ minutes of sanding by hand for an entire building, and if you are doing several buildings, then it would get pretty old pretty quickly.
If you don't have a power sander (bench top belt sander is highly preferable) and you have no patience -> not recommended...if you have patience -> recommended.
They do have an excellent range of thematic buildings, and are adding to the range all the time, which makes them highly attractive as well, to me anyway...the only thing missing at the moment are really tall buildings, like apartment block sized buildings, but they may do those eventually.
I think my next purchase will either be a Clan Genetic Depository, a Fusion Reactor, or the HPG (Interstellar Communications) Buildings.