Trans Dem 2.5.1 works great and works with TS12 SP1. The advantages of TD2.5.1, in particular the 64-bit version, is the ability to handle much larger maps, and import GeoPDF maps which it converts to placable images. This latter feature is great for importing historical maps and others in the GeoPDF format.
TD2.3 works okay with TS12, but with the larger 1arcsecond downloads, it tends to choke and crash on these. The 64-bit 2.5.x handles these maps much better.