I run all freeware, a mix of various models including TFS, AIA, FAIB, AIM and UTT. Some are FSX native and others aren't. They look amazing in FSX and P3d v2.Performance wise, there's a hit but it looks AMAZING and still runs well.
It really comes down to what you are looking for. Ease of use at the expense of model quality and realism then go with My Traffic 2013, UT2 models and repaints are MUCH nicer but it's kinda of quirky and isn't supported in P3d (although getting it to work isn't difficult).. The freeware route requires setup and time, but it's BY FAR the best end result.