(1) Installing issues:
I have installed the magnets four times, and each time ran into the same issue - when guiding the magnet on the inside, it tends to leap slightly out of my hand towards the outside support's magnet (and the outside support shifts towards the inside magnet), leading to the final position being misaligned from where I wanted it. Usually it's only by a small amount so not a big deal, but for one of my installs, I forgot to hold on to the support so it ended up crooked by a few centimeters (was harder than usual to move my hand around in this particular guitar, so I think I reflexively used my other hand to shift something and then the magnets snapped together while my hand was off). I decided not to bother trying to fix it because I was hoping it wouldn't end up being too bad, and I’ve read that it was very difficult to remove the strips, especially with the awkward angle inside the guitar. (Unfortunately, I didn’t notice until a few days later that the support was crooked enough that one of the pads was now pressing into the guitar at a slight angle, which is probably bad for the pad; ended up loosening all the strings again, then used a hand-warmer to attempt to loosen up the strip. Was still not able to pull it off by pulling the top, but I ended up being able to half-twist half-pull the magnet off without that much trouble, not sure how much the heat helped)
In the instructions, while "hold firmly to the magnet" is bolded, the "hold the support" is not bolded and is earlier above on the page, might be better to write as "Holding firmly on to both the support and the magnet, …". There's not a whole lot that can be done about the magnet jumping behavior otherwise I think, the magnets are too powerful and the angle is awkward inside the guitar, plus I can't see anything so I can’t try to align it to land directly on top of the outside magnet. I've always done the upper-body magnet first but it might be better to do the lower-body first, since the upper-body is probably easier to take off?
(2) Adjustability issues:
The crooked support leads me to the second issue, the limits with adjustability. In my case, the crookedness could’ve been mitigated if the support feet could be rotationally adjusted even a little bit, but it can't be rotated. Even with my other installations that aren't misaligned, I've found myself wishing that I could rotate it sometimes, so I can move the guitar body closer under my right arm (with the headstock angled further away from me), which is something I've found to be more comfortable sometimes. Unfortunately since the guitar sides are curved and the magnets are flat, I have to place the support in parallel with the guitar body – it can't be put at an angle because then the magnets won't rest flat on the guitar (which will make the support less stable and likely damage the cork over time).
Also, while the support can be adjusted significantly prior to picking the final location, once the magnets are locked, the support is significantly limited in its adjustment range. E.g. for my acoustic, I usually want to play with my acoustic guitar on the left leg in classical position, but sometimes I want to play traditionally on the right leg; but that requires a significantly different adjustment, which cannot be fully done with my current locked-in magnet positions (to be fair, this support is more for classicals). Or, I have bigger guitars and the magnets are in different places along the body, so the support’s arm height needs to be adjusted every time. Not sure if that one has a fix though, I ended up just buying a second support to not have to adjust constantly by guitar size.
(3) Review issues:
This is unrelated to the guitar support, but I didn't like how there seems to be a time limit on leaving a review? This is my second support, as I mentioned; I bought the first one back in mid-Nov, then got an email requesting feedback, but waited for a few months of using it until attempting to review it in early Feb. However when I attempted to submit that review, nothing happened; if there's a time limit to leave a review, it should be mentioned somewhere (I don't see why we shouldn't be allowed to review a product we ordered at any time from the website either if we're logged in – but the review button only showed up when I started the review via the email, otherwise there's no option to leave a review even while logged in).
Overall:
Assuming the magnets are in the correct place, and you don't have much adjusting needs in general, the support is good; it’s sturdy and it's easy to attach and detach which is all way better than the suction cup supports. However it’s definitely a tedious process where little things can go wrong, and the support’s adjustability definitely has limits. Despite the issues, overall I do still like the support, hence the 4-star rating.