I have two benches. And the cheaper one is what I am sitting on daily. The X-style bench (Model H&A K5BP) came as part of the bundle with my DP. It looks cheap, but is surprisingly sturdy and comfortable. The big draw back is it has only 4 distinct heights.
I went through a period of being obsessed trying seat height in big and small increments, hoping to find the "perfect" height. That lead me to buy the adjustable bench (Starfavor). It's a good looking bench for $100. Quality looks great in terms of cosmetic and assembly. However, the material (wood and metal) are on the slim side, so most of the nuts and bolts needs repeated tightening for the first couple of weeks until they stretch and settle. It's sturdy. I have not found it drooping. It does have a little bit of squeak like @WieWaldi's.
Well, my obsession came to an end when started learning Peter Feuchtwanger's exercises with @Seeker. Peter requires a very low seat height. And the Starfavor cannot go low enough. I set the X bench to its lowest setting and that's what I've been sitting on for the past 5 months.
You can see in my recent videos I am sitting very low, with bottom of elbow well below the key surface. Several people noticed and pointed it out. But that seating height has been working well for me. One important thing I learned is sitting low does not necessarily introduce shoulder tension, but quite the contrary if done properly as I am taught by @Seeker, and as Peter Feuchtwanger wrote:
"For instance, Glenn Gould, in spite of his perfect use of hands and arms, sat so low at the keyboard that it resulted in him lifting his shoulders unnaturally, creating back pain and numb fingers and immense tension in his neck. The tension Gould incurred was due to the wrong way of sitting at the keyboard for so many years, and could even have been partly responsible for his untimely death. By contrast, Louis Kentner, who sat almost as low as Gould but used his body correctly, suffered no ill effects and played magnificently well into old age."
