SenorPlatanoI was going to get the Markus, but tried it, and it just wasn't that good. No real support for lower back, and the one for your head is not good either. Also, the construction is pretty basic, although it looks sturdy.
A great chair is Office4You RAGUSA, if you can get it (the brand is Estonian, and the chair costs about $150). The head support could be sturdier, and it won't suit you if you are more than 180 cm tall, but it is way more comfortable than the Markus. Everyone who tried it, confirmed than it was incredible comfy. I think i will get it if I get a chance to try it once again. I think it was even more comfortable than the DX Racer chairs, which is insane at this price point. It's not a Steelcase, you know.