I've used both WOAI and UT2 in FSX and spent countless hours with AIFP collecting and creating custom AI routes. My thoughts are these for P3Dv4:
1. I purchased UT2 for FSX with the hope that I would no longer have to spend so much time managing AI traffic. Unfortunately, I discovered I was still spending time managing or replacing, wrong models, poor models, obsolete routes and airlines and removing old liveries, etc.
2. The best looking and performing real world AI situation I've had is a combination of WOAI and AIFP. However, it was a lot of work, and time consuming. Several key models are not P3dv4 compatible yet so I'm reluctant to go down this road again.
3. I will consider purchasing an all inclusive AI program like global traffic when the developer takes some of that responsibility off the user and provides more frequent updates and support instead of just a set of tools for DIY traffic. I already have access to those tools.
I'm looking forward to seeing what Traffic Global has to offer.