In that case Mal, you'd better buy an SDM or an Obsession.
I've had my hands on one or two GSO dobsonians of some age and possibly not great maintenance, and they were a horrible movement to my touch, particularly Az - far too much "stiction". Probably dust and muck got into the base. I move a new one in the showroom and it feels guite good. (But operation out in the cold/wet can be quite different to warm/dry of indoors.)
I preferred to improve mine. I'm a tinkerer. No problem for me that I take something I bought and make it better - I regularly do that. I like getting improved performance out of something I bought for a mediocre price by using a little bit if ingenuity, effort and a few parts.