I've had great performance from the various products I've used or installed in the past (my rides, other friend's rides or even agency vehicles). I installed some E3s and an E66 on an old Jeep Cherokee roughly four years ago and aside from a lil UV exposure to the lenses, they're still holding up well.
I did an install about two and a half years ago for a local
FD who upgraded a ladder truck and an engine, which required them to purchase multiple Whelen 700 series LEDs.
SNM provided the best price for bulk purchasing compared to the other big webstores.
Only issue I've ever had with a product happened just a week ago, being their brand of LED beacons. The issue I had was the provided screws did not thread properly into the light on three of the eight holes. As far as the performance of the light, can't complain one bit, ESPECIALLY for the price. I set them on a simple, slow on/off pattern for full brightness and they rock!