as long as everyone is sharing bad experiences with Black Bear, I'll temper them with my good experiences where I've installed Justin's tunes in friends' rides:
2001 1500 4.8 - FASST Intake 102mm, built trans, etc. Emissions deleted. Great tuning. Asked for logs and tweaked same several times. Very happy. Added a Procharger and retuned. Everyone happy, including all 4 neutrals in the 4l60, LMAO.
2011 1500 5.3 with 6-speed auto - excellent tuning and followed up with logging. He replied back quickly and tweaked the tune slightly - extremely happy.
2016 Chevy SS - big cam, headers, beehive springs, intake, exhaust etc. - great tune. Super happy. Again, logged and sent back and no need for tweaking tune.
2011 Yukon XL 6.2 with 6 speed - WOW! Awesome tune (his wife has one, so he must have spent time dialing this in). This big girl is an animal.
2007.5 1500 with 5.3 and 4l60 with corvette servo - another excellent tune and never bothered sending back a log, lol.
Tralblazer SS with 6.0 and headers - I think he was like 390 on the dyno, but it's been a while.
I think that there's two major things going on with the happy gassers I've installed his tuning on. First, any of the trucks/cars with a tip-in delay feel like they pick up tons of power because the engine is more responsive to input. The second is the transmission tuning helps a lot as well. You won't see Dmax sized gains, but you will get a lot more responsive and crisp feeling behind the wheel. .
Good luck in whatever you go with!