It's a beast. I purchased it specifically to compliment my newly constructed wood oven to assist in making stronger pizza bases. There's no other style of mixer that can knead dough like a spiral mixer and this is the cheapest mixer you can buy. You may find second hand commercial mixers BUT you need to be wary of the size and weight of some of these commercial ones. It's not uncommon to find them in excess of 80kg.
This one is around 35kg but I've never weighed it which means it's quite heavy to move around will most likely occupy a permanent place on your bench. It's not going to live in your corner cupboard and come out occasionally as you wont get it in and out. My wife nearly dropped it trying to move it from the kitchen bench to the floor and she's quite fit and reasonably strong.
Cleaning the unit is no issue. I was worried about not having a removable bowl but the final dough that comes out is so incredibly sticky that nearly all of it has come out on its own and you can wipe the rest out with a rag in about 2 minutes.
I found claims online that this unit mixes too fast. I can't speak to it being much of a problem but the dough is reasonably warm after 15-18 minutes of mixing unless you use chilled water from the fridge or throw a few ice cubes in.
I've now used the mixer on four separate occasions and found it's really well sized to do 12 balls of dough at once with a weight of 270g per ball. It doesn't feel like it's struggling to do it so you could probably push more in it but dough ball trays fit 12 balls nicely so it's a good size to work with. I was using a recipe derived from Vito Lacopelli's youtube videos which involved a poolish mix and 65% hydration and was very happy with the results. A typical batch looks like:
Poolish: 383g water, 383g flour, 6g yeast, 6g honey. Mix and let stand for 1 hour on the bench and then 24h in the fridge.
Next day: Add 1581g flour to the mixer, 51g of salt, then the poolish from the fridge and then mix about 80% of 893g of water, reserving the final 20% of the water for mixing directly onto dry patches of flour at the base of the bowl while it's mixing to help it pick up faster.
I put it through its paces for a party and made 108 dough balls in 9 consecutive batches back to back. The unit never complained but you can smell the grease on the chain warming up and the switches on the side were warming up too. It's probably not designed to be used commercially (and you wouldn't with such a small bowl) but it handled the task perfectly and would happily do it again.
If you were on the fence about getting a mixer for your oven and weren't sure if this was the right one, or if you're spending too much money, etc. Just know that you cannot find anything cheaper or smaller and this thing is perfect for your house.
Rob 
For the Price, its great. 
