What abuse are you talking about? Personally I've had as much difficulty flying OF online as I've had with AF (which is very little). Of course I haven't flown online with a lot of people at once, but as you know the guys at GF have flown perfectly fine quite a few times with 15-20 ppl (IIRC).
Abuse: Here's one major one
1) Multiple players connecting and disconnecting from a server for days at a time
This is just one example, but there are quite a few more subtle things that have been known in the older MP code of OF.
OF suffers from many of the issues that AF has corrected in it's MP. It's quite different in fact and is the reason for being able to handle more pilots with greater ease than OF. Also, the smoothness in close positional updates in AF exceed that of OF.
In OF with large MP missions it is far more common to have anomolies such as disappearing AB textures, AGG/DeAGG issues, losing AWACS communications, RWR, and other packets that are routinely dropped. This is something that you almost never see as a problem with AF. You also see individual CTDs on larger MP flights in OF than you do with AF. Most OF supporters would suggest that it is most likely the individuals fault for not being configged properly, but doesn't that only lend more credence to my point even if that would be the case?
OFers have openly admitted that the installation is far from optimized both in MP and in relative stability by comparison to AF (due to it's ability to being tweaked, configed, modded amongst other things).
If you're flying with less than 8 people in OF you've got greater chances of success without problems, but they're still likely to occur, whereas in AF it is quite easy to have 15+ pilots flying without issue (warping, dropped packets, other anomolies).
You'd have to partake in large MP flights that push the code to its potential before making a sweeping judgement on which would be considered more stable. I've actively flown in both variations with large numbers of pilots and know for certain that OF is not on par with AF in terms of MP stability. Can OF host large numbers of pilots in the campaign? Sure, but not without painstaking care, or the usual handful of problems with pilots having to disconnect, or the host reset the server because of one reason or the other. The time it takes and care it takes to get a large MP flight stable and operational is far more anal retentive by comparison to AF, which goes off a greater percentage of the time without a hitch.