I haven't tried the ErgoChair, but I did buy their cheaper model, the MyoChair
The company does come off a little sketchy to me. I've heard that they like to offer a lot of rewards and kickbacks to reviewers, so a lot of reviews seem favourable. I could be wrong on this, but I'm pretty sure their chairs are just re-badged chairs from China. So they don't always have stock and you can wait a month or more before your chair is shipped.
That said, my overall experience was pretty good. I bought on black friday and it took about 2 weeks before they shipped and it arrived relatively quickly after that. I'm generally happy with the chair, I find it comfortable and I don't feel like I got a cheap piece of **** or anything. So, I'm going to focus on the negative, but keep in mind I'm content with my purchase.
I got the headrest package, which also comes with the footrest. I want a headrest, but the footrest is kind of awkward and I'd probably never or rarely use it. But you it's either both or none.
The seat itself is firm. I'm coming from a LaZBoy that was super soft and padded. The MyoChair seat is hard, but at least you don't bottom out on it and I don't really find it uncomfortable.
The armrests aren't padded, but it's more of a soft plastic. It's decent. But I find them a bit too far forward. Not a big deal.
The headrest is a bit flimsy. It had an adjustable slider that snaps at different levels. I find it rattles a bit, which is kind of annoying.
The back rest is fine. It's mesh, but I find it at least as comfortable as my super-padded LaZBoy was. And it's much cooler on the back. And won't flake off because it isn't made of garbage synthetic leather.
It leans back and you can lock it in at 3 different distances of recline. But only the back leans back, the seat itself doesn't pitch up.
At first it was absolutely silent. But I'm starting to notice some creaks. Not nearly as bad as the LaZBoy was. The armrest just started creaking, but I tend to lean on them hard. The back is mostly okay if I lean back, but for some reason if I put only slight pressure on the back it creaks. It might just be a matter of re-tightening some stuff.
If you're interested in the ErgoChair, I'd take a good look at what features you're getting compared to the MyoChair and decide whether it's worth the fairly significant price jump.