I'll show 5star a little bit of love here. They are very responsive and customer svc is excellent. Their 93 perf tune is very very fast and I am very happy with it. Compared to stock, it is night & day. However, there have been a few minor hiccups that I've been trying to iron out to no avail. I had previously scoured the forums RE tunes and think the consensus is ZFG. Either that, or ZFG has the happiest, most active forum members lol. Unfortunately for me, I missed the boat by 1 day and despite us having numerous conversations, Adam refused to tune my rig until he got his EPA thing sorted. I was bitter about it for a week or so, ordered the 5-star and have been enjoying it ever since. I still plan to get my truck tuned by ZFG and Adam assured me I would be one of the first 10 (remains to be seen).
I think the main difference with ZFG is datalogging and the additional level of customization he can achieve therefrom. I have requested several tweaks to various tunes from 5-star based upon my descriptions of what I'm experiencing and what i want it to feel like, and most of the revised tunes were no better than the original. In fact, most were worse. I have requested them to datalog the issues, but they they still have not done so as I dont think they support datalogging on the HPT RTD device just yet. To that end, I still think they are a good tuning option esp. in ZFG's absence. Many others seem happy with theirs and if you are not as picky as I am, you will probably be very happy with 5-star. Either way, I will definitely post a thread here once I get tuned by ZFG with some more insight.