I can not speak to the specifics of BR07 vs. BR04, as I have neither set.
But I am quite familiar with the "older style" H&R figures.
Most of the figures were modeled/mastered and in production by the mid-1990s. I started buying H&R infantry about that time.
At that time I considered them far superior to any other offering. GHQ was just scaling up their "en bloc" style figures, after giving up on individual figures that were widely criticized by gamers as too fragile. C-in-C stayed on the too-fragile path, with some particularly awkward poses and a selection of poses that just left me scratching my head (maybe I can get by without any identifiable BAR men, but why do I want so many WW2 US Army figures marching with slung rifles?). Scotia was just not consistent enough (some good figures, some that looked like sci-fi space robots). And Skytrex were just not good enough across the board (mercifully they sold off their 6mm line and focused elsewhere).
H&R were (and the old sets still are) consistent, robust enough for gaming use, and in useful combinations of poses. But they were never exceptionally detailed or crisp. No facial features to speak of. Often you can't see the foot for the leg (just a "trunk" to the base). Much of the personal kit (backpacks, canteens, etc.) are just bumps or blobs.
But I always found them good enough. I can visually distinguish the soldier with an LMG or an SMG from a rifleman. I can see the gunner's No. 2 carrying an ammo box. The German helmets are visually different from the Russian helmets. And I can use paints to distinguish the face under the helmet, even if there aren't a lot of facial features, or paint to distinguish the boot or shoe from the trouser, even if it is actually casted more like an elephant's leg/foot.
Since the mid-1990s other vendors have come in with some nicely modelled infantry figures. Baccus comes to mind, but GHQ with their "individual infantry" are the real benchmark for detail and crisp castings. I just love the GHQ figures, wow do they paint up nicely. And they seem to be robust enough (although I have not compiled nearly as many gaming hours with GHQ figures as I have with my H&R WW2 Soviets). But sometimes the better poses of the H&R stuff is still attractive to me. In fact I am just finishing a WW2 US Army infantry force with H&R "old" castings, to replace the C-in-C based units that have been in my "ready forces" box since the late 1980s.
All of that said, the older H&R stuff is … older. They quality of the figures was quite impressive 25 years ago. But now they are showing their age. Not only has the state of the industry moved forward, but old masters degrade in time, and you can see that the castings are just not quite as crisp as they originally were (I still have some unpainted sets bought more than 15 years ago).
Everything I have seen of the newer H&R stuff has impressed me. The new management/ownership, and the new modelling, seem to have retained most of the old positive values, and added crisper details. I don't have much of the newer stuff in my collection yet, but I've gamed with some of the newer pieces from gaming friend's collections. I give very high marks.
All opinion, of course. Take it and use it, or leave it by the dside of the digital road as you see fit.
-Mark
(aka: Mk 1)