I bought a fully loaded Herman Miller Aeron Remastered Chair, and have been sitting on it for the last two weeks. Fun Fact: Aeron stands for "an expensive Ron". So you're asking what it's like to sit on Ron?
Of course it's good. It has to be good. It's an expensive chair, it better be good. I've sat on a cheap DX Racer for the last 7 years, which isn't a fair comparison, but whattayawannado.
First of all, this thing is like a hammock for your butt. It doesn't get uncomfortable even after hours and hours of sitting. And the tilting mechanism – gosh! – it is so well adjusted. When I simply lean back, I sit comfortably straight and it supports my back. And when I use a little more pressure, it tilts back (because I didn't lock the back rest). But I don't tilt back until it locks, I just stop wherever feels good to me. And then I comfortably lean back and the thing still supports my back. That's crazy to me! I don't need to turn any knobs to change if I want to sit straight or lean back, so I change my sitting position automatically whenever I feel like it.
It's so comfortable. You can't really sit wrong on it, you're automatically in the correct position. The "PostureFit" lumbar support pads I don't really feel pressing against my back, but I do feel that it supports me. The lack of a missing headrest made me a bit sceptical at first, but I don't miss the headrest at all. I guess those fancy engineers at Herman Miller were right about that one.
People online reported that they have back pains in the first weeks because they didn't sit straight for years, but I only felt it for 2 days or so. And then it actually relieved my most noticeable back pain! I always had this tension next to my right shoulder blade, and now it's gone.
So is it worth it? This thing has 12 years guarantee. This comes down to a bit more than 100€ a year. And they usually last way longer. That's worth it to me.