For First Source Wireless as a company, purchasing process was simple and shipping was quick. They set tracking numbers and emailed updates at each set during the order.
Just started using the ComTac VI headset in a helmet mount setup and so far they are superior to my MSA sorbin headset in sound reduction and ambient audio quality/radio audio. A little early to say if they will be as durable, but I have an original Peltor ComTac from the late 1990s that I still use when I need an extra set at the range and those have been solid.
I have not tried the NIB feature yet, only messed with the controls, but seems fairly user friendly. I will say, they could have come up with a better name than "NIB" (Natural Interaction Behavior), I never remember what it stands for and it really doesn't describe the function (short range communication feature that seamlessly connects and migrates between headset groups as the wearer moves).
Switching over to the ACH ballistic helmet mount was far easier with the Peltor versus the MSA. The MSA headset required purchasing ARC adapters, then little metal adapters to then fit the headset and ARC together, a tiny set of snap ring pliers and lots of patience. The Peltor headset came with the ARC swivels and adapters that connected directly to the headset, it was switched over in a matter of minutes and can easily be switched back if needed. The MSA had some permanent modifications to make them helmet mountable.
Battery access is better with the Peltor ComTac VI also, on the MSA it can be a real pain swapping batteries, where the Peltor has o-ringed covers that are popped off. I haven't used them to the point where the batteries need replacing, so I can't speak to the battery life yet.
I don't remember the original price for the MSA sorbin headset, but MSA didn't come with as many features and/or adapters. The Peltor ComTac VI came with a replacement set of gel cushions, ACH adapter and seems to have a lot more capability.