I have some experience with 1/72 kits.
Dragon kits are the great, obviously--really just shrunk-down versions of their 1/35 line, same instruction sheets and all. The real dogs about them are the darned 1-piece tracks. Atleast half of them you build are too long, and of course, you can't sag 'em. Bummer. I've actually bought Revell kits just to use the indy link tracks from them on the Dragon kits. Of course, on modern tanks like the Leopard and Abrams, you can hide that rack splice under the skirts.
Revelll have some decent, if older kits, and most come with indy tracks, which I much prefer. Some of the detail is heavier in scale, but you can get around some of it with some minor scratchbuilding.
There are a few oddball companies out there like ACE and UTZ (?). The ACE Waffentrager was one of the only models that I actually gave up on and chucked it---but their Steyr tractor is kinda nice, with PE tracks, if you can believe that. I haven't been able to convince myself to plop down the money that UTZ is asking for some of their kits, but they have some very interesting odd ball subjects and look like they may have great detail?
The "new" Italeri 1/72 line is mostly re-pops of old ESCI kits and some older Revell kits, which used to be the standard, but are clunky now.
Trumpeter also has some nice models, but I have to say that their one-piece tracks must be made of something like silicon, because I could NOT get them to join with literally ANY glue I tried, not even super glue. I wound up having to epoxy them, which made a big bulge in them that I then had to hide. What a disappointmentr that was.
PST does some neat Russian subjects--KVs, Stalins, SU-series, and are fairly nice kits when built, but be prepared to replace hatches with scratchbuilt ones, as the plastic is really thick. They also feature indy link tracks. Here's the PST KV-II in 1/72
