I actually have a DX Racer, but unfortunately went with one of the cheapest models. It's actually a really comfortable chair, even when I would spend like 8 hours straight in it.. and with that said, my back is pretty messed up. I have 3 herniated discs and one torn leaking disc, three bulging discs, kyphosis, three back surgeries, etc.. but my chair is still comfortable to me. Although, I do wish I had gone with a more expensive model. Unfortunately I couldn't spend like $1000 on a Herman Miller... so I went with a DX Racer and don't regret it. I just regret not getting a King or Iron series.
I'm 6'1" so I needed something to accommodate a tall person, which is why I didn't go for the Drifting series (Even though I wanted one because that series has a pink model) and went with the Racing series instead.
As much as I do like my chair, and it's comfortable even with my screwed up spine, IF you DO have the money for a much better chair... I would say go for it. If I had had more money to spend, I'd have gone with a Herman Miller haha. Or at least gone with a higher DX Racer model.