Because of all of the factors you have to "learn" to be able to use this mixer properly there is lots of room for inconsistency. I have made amazing dough with the santos, and then the next time, trying to do everything exactly like I did the time before, the dough would turn out to be sub par. I spent at least 5 months using it a few times a week, and still couldn't get to the point where I was making consistent pies. The santos mixer only has one speed, and that speed is double the slow speed of an italian fork mixer, so the window of optimum mixing is very small. I think one minute extra or not enough on this machine can make or break a batch. Between all the babysitting you have to do with this mixer, the high price, waiting for months to have one imported, and the fact that most of my batches in it were not top quality, I give this one a big thumbs down. Having said all that, I think that if you are really really good at mixing dough, and don't mind standing over the thing for the whole mix, It can make an excellent dough for some people, just not me. I look at SFNM's pies and they are all gorgeous, and I haven't heard any talk from him of bad batches. I know if I put all my ingredients into a spiral mixer, or even my bosch mixer, I can come back 8 minutes later and the dough is perfect and the same every time. If the batch turns out bad it is almost always because I f.....d up the rise, or some other factor like that. It should also be known that forum member scpizza has modified his santos to run at half speed. I think that all my issues with the santos were because it was running so fast, and if it were running at the right (italian) speed, this would be an amazing mixer. Of course you would still have the variable of having to stand by it and make sure the bowl is rotating at the right speed, which is another hurdle you don't have to deal with with a typical commercial italian fork mixer.
If I were to be able to choose between the sp5 spiral mixer and the santos, I would definitely go with the sp5. If I owned a pizzeria and had the extra cash around, I would go for a pietroberto fork mixer. Unfortunately their smallest model is still to big to use in a home setting.