Nope, I've never heard of it.
I'm also a fan of Force on Force, however.
I'm actually a bit surprised that you haven't received more responses. Modern-ish systems get brought up from time to time, and there are a few systems that you'll regularly see mentioned whenever someone asks about a favorite.
Anyway, getting back to Danger Close, it looks like there are a handful of reviews of it online, though if you go searching for them you'll need to clarify that you're looking for reviews of the game and not the movie.
The rules are quite brief, which I'm guessing means that the system is fairly simple to run. But at the same time, I'm also guessing that it doesn't delve too far beyond the basics. And you're forced to come up with the stats for most of the conflicts that you wish to fight.
Force on Force is mostly the opposite of this. The system itself is simple and effects based. But the rulebook is *very* exhaustive in providing rules for all sorts of different situations. For instance, close air support from fast movers works differently than support from a helicopter. So you've got rules to cover most any situation. But at the same time, you can safely ignore most of them because - for example - the number of times you'll actually have fast mover support in a game at this level is quite low. But if you do have it, you can look it up beforehand just for that scenario. Adding to that, there are supplemental books that cover the ins and outs of a number of post-Korean conflicts. So if you want to run scenarios in Vietnam, you're covered. Same if you want to run scenarios set during the UN intervention into the Somali Civil War. The books are hardly exhaustive. But they cover some of the wars that players (particularly American players) are more likely to be interested in.
