I bought the set as a replacement for an unbranded normal tuning machine. I chose this since it's a locking tuner from a well-known brand and it's cheap. When I first saw the product, I was a bit worried because the top lock did not give an impression of being strong enough. But after I installed it and the strings, I was amazed by how strong and reliable it is. Moreover, it is also not that hard to lock, even though a screwdriver was needed. With a back lock tuner, you don't need any tool and can just use your hand, but to get it lock you need more hand power. The top lock is actually easier to work with.
Now after few days the tuning stability is good, no problem at all. It's very reliable, as a locking tuner set should be.