I'd personally stay away.
No one or thing is perfect and things often do go wrong. You don't know how good a company is until something does go wrong, as you get to see how they deal with it and their customer service for what could cost them money.
Going off the 1 star
reviews, and how they deal with them, that would immediately put me off.
So that's the first red flag for me.
On the tuning front, do they have a Dyno? They claim to be using custom maps not generic files. So how are they making sure the maps are right? Most companies that offer true custom tuning will have it on a Dyno first. Also generic files are not all bad when they come from companies that have created these over 1,000s of miles across multiple cars, and lots of R&D, but they are generally only sold through their approved dealers (think Racingline and Revo).
So no dyno yet custom tunes? Second red flag.
BUT That is just my opinion from my own short research on the company. They could very well be an amazing company and deliver exactly what they say. The 1 star
reviews may very well be FAKE NEWS, and the customer's own issues. But again, most reputable tuners will check the car over first anyway. And if there are any obvious faults, not work on the car if its detrimental to the car itself, until they're sorted.
Finally, the bit that says remaps are not harmful to the engine. Sorry but this isn't exactly correct. Engines are made with tolerances in mind, and the standard maps work to ensure the car is within these tolerances. The generics maps offered by the likes of Racingline and Revo again do something similar, which is why they will not make the peak numbers a custom tune will. But they are still eating into the tolerances. So they are putting more strain on the parts giving you less wiggle room for things to go wrong. Standard cars go wrong and fail, cars being pushed more are more likely to go wrong. You can have a standard car break within 5,000 miles, and a tuned car last 100,000 miles without an issue. you take your chances and roll the dice.
Anyway just my 2p