I got it as a family present this last July.
I didn't know this product, but I found it really useful at first.
First point: In terms of tuning, it's better if you tune two times, because the first time it's not that precise, even if it's not bad.
The second point is more important: The tuners are very fragile, so you need be careful when you change strings. But that's not all, twice I've had a tuner blocked while simply tuning. I haven't had the time to change strings.
I play open tunings a lot, so I use the tuners quite a bit, but this product is made for that, isn't it?
So, replacing the tuner in question poses not a problem, because they can all be taken off independently. But finding the tuners for this system is a job in itself and I'm still not done!
If I had to choose today, with the little experience I've had with this tool, I would go for classic and manual tuners, given their fragility and price!
I think they are inadequate. If the system works it's great, but if one of the tuners gets blocked, then it's game over, you won't be able to play your favorite instrument.