I personally prefer JoinFS to anything else for these reasons:
1. I fly primarily military missions with Tacpack. JoinFS supports this not perfectly but reasonably well.
2. We sometimes have between 10 and 20 people in a session. This would reduce either a P3D or FSX direct connect session to a whimpering mess and crash to desktop. Six players is about the max that you can get on a direct connect session stably.
3. JoinFS Supports FSX, FSX Steam, P3D, P3Dv4, and X-Plane. I personally am flying quite a bit of X-Plane lately.
4. JoinFS is extremely stable if all players lock their frame rates below 35. If a player has his Frame rates set above 35, He/She will be jerky/jumpy when you are in close proximity. Similar to the FSHost "Jitterbug".
5. Setting up a 24/7 server is a breeze with JoinFS.
If you need any help or are interested in test sessions, please shoot me a PM and I will be happy to oblige.