I love it! I'd say it's geared more towards the "casual" tuner, someone who just wants to plug it in and go. With that said, the JB4 community is full of people much more experienced with tuning who are comfortable with modifying parameters, interpreting the logs, and then making adjustments to suit their needs. So really it can go either way.
I'm very happy with mine. I happened to buy mine secondhand from a user here, who had it installed on a CX-5 turbo. They sold theirs because they moved to a different car.
As far as numbers go, I did test it out with a few 0-100km/h runs, comparing Map 0 (disabled) to Map 2 (93 octane). At the time, I only had access to Shell 91, but I sent a Map 1 log to Terry and he said I could run Map 2. I thought I posted pictures somewhere, but from what I recall, Map 0 resulted in a 0-100 time of 7.2 or 7.3s. The next run with Map 2 enabled gave me a time of 6.7-6.8s. It just feels more powerful all around. Since 93 became available in my area, I've been fueling up with that, but never bothered to check the 0-100 time, and then I traded the 2018 in for the 2022. When I get it installed on the 2022, I'll try to do another comparison.
Also, I noticed that Burger Tuning recently developed their own app, meant to be used with a different bluetooth module. Normally you'd have to pay an extra $150 USD for the bluetooth option, then pay for the JB4 Mobile app (something like $20-30 USD), which was developed and is supported by Dmac Mobile. I think back in May this year, they released the JB4PRO app, which was developed in-house, and is free. It uses a different bluetooth module, which is only $79 USD. Terry at Burger Tuning says that there's no real advantage to one or the other outside of price and presentation, so if I were buying new, I'd opt for the cheaper JB4PRO option.