Try an online games sight like EB games or something for OFP. The differences between the products are not sufficent for the average gamer. Besides the next game in the OFP franchise will be released shortly.
Yeah if you're willing to shell out 1200$ for the full VBS package, then it's a pretty good sim, but it is basically just an updated version of vanilla OFP, designed for government use and now available to the public, but with the governmental price tag
OFP is just great. I've been playing it since its release in 2002, been with the same squad since then, and it's still the only game I play seriously.