If you did't track stats then it's not important. GHIN has HBH tracking and it sucks. My GolfNet HI and GHIN HI are identical, accuracy isn't an issue. Surely you didn't miss that stat tracking is important to me if you took the time to quote my post. It's not unreasonable to believe that if the USGA wants to monopolize the market they should offer the best product. Currently they don't.
I use GolfNet myself (but have admittedly never tried GHIN). I shopped around in May this year, and found that the GolfNet service was exactly what I needed. Hole-by-hole stat tracking and analysis, plus a USGA-approved handicap. The price was significantly less than the price for handicaps at local clubs (via GHIN), plus GolfNet gave me the great stats and analysis tools. I asked a couple local clubs about tools for analyzing my rounds that I would get with their handicap, and they didn't seem very knowledgeable. Otherwise, if you just want a handicap, there's probably zero difference. The calculation is pretty simple. It's the features that I saw from GolfNet for analyzing your game that stood out for me- well, that and price was about half.