I got into making bread and pizza dough from home ground wheat flour, and started with small dough batches to test out various combinations of red and wheat flour. The first mixer I used was the Bosch Universal ( not the plus ) that I got off ebay. It had the dreaded dough wrapping around the center column with small batches. I then got a Compact, and it does a great job with small batches and high hydration, but can move around a bit. I saw a Concept on ebay that was not working, bought and get it working, so I decided to do a head to head comparison, before I sold off the Universal. The Concept is not well know, but came out after the Universal, but before the Plus - it was not a real success, and so it was stopped. It uses the same bowl size as the Universal and the Plus . When it first came out, it had what they later called European dough hooks - apparently a lot of complaints were made, so they started offering what the called the US or heavy duty dough hooks. I used the European Dough hook on the Concept because from a prior trial, I got the dough wrapping around the center column when using the US - Heavy Duty Dough hook. The first photo shows all 4 dough hooks. As you can see, the Compact Hook looks like a toy, and the Concept US Heavy Duty Dough hook is a monster.
The test was to knead a small batch of KABF - 200 grams Flour, 130 water, 4 grams Salt .3 yeast. My idea was to start all 3 mixers with the same stuff, then stop every minute and see how well each one did. It didn't work out exactly that way, because I soon realized that Speed 1 on the Universal, was much faster than Speed 1 on the Concept, and it was hard to judge the speed of the Compact because it has a totally different motion than the other two. So that threw everything off, but I did get some interesting results. First, I started all three by putting the water in the bowl, then using pulse on the Universal, and the slowest speed on the other two, then turned up the speed for the rest of the minute. By the end of the 3rd minute, the Universal had a pretty nicely kneaded ball, and the Compact had still not incorporated all the ingredients, the Concept was behind the Universal, though the Universal's first speed is probably about the same as Speed 3 on the Concept. By the end of the 4 th minute, the Universal had a pretty well kneaded dough, the Concept was slightly behind, the Compact lagged further ,but I had been running it at 2, so I turned it up to Speed 3. By the end of the 5th minute, they were all pretty close. Good enough to go into the fridge for long ferment, but no window pane. Right after I started after the 5th minute, the Universal got the dreaded wrap around the center column. I tried to move the dough back to the bottom, but it would go right back to the column. I measured the temp and it was 77.4. The dough in the Concept was 76.3 and felt a little lumpy, but passed the window pane test. By that time, I had turned the Compact up to speed 3 for a the last few steps, and the dough temp was 80.1. it felt smoother than the Concept, but did not do as nice a window pane.
So my conclusions were if you want to get a good knead, but don't need to hit a window pane, any of the three will handle very small batches of dough at 66% hydration. If you go just a little too far with the Universal, it will wrap around the column. It is possible that you can chill it to get it to knead again. The Compact seems less efficient, but it keeps chugging along and had no problem with this small batch. The Concept seems steadier than the Compact when mixing, and can handle a small batch with the European Dough Hook. With the US Heavy Duty hook, it was no better, and maybe a little worse, than the Universal.