With the number of KA Professional 600’s and its derivatives out there, a small number of them are certain to exhibit little yellow citrus tendencies. My older Professional 6 is still going strong after six years and if you follow the very good advice to limit your dough to 7-8 cups [1 kg or 35 oz] of flour chances are very good that yours will live a long life too.
If it does not, the K6 platform is the easiest mixer around to repair without sending it off to trained technician and parts are available all over the internet at reasonable prices.
For making bread, a lift bowl mixer is a lot more stable when kneading under load than a tilt head. To remove the bowl from a lift bowl the agitator has to be removed and dropped into the bowl before the bowl is lifted from its pins. It is a motion that becomes natural and normal after a few uses. I have a tilt head and a lift bowl and after using both for many years, I don’t really have a preference except that the big lift bowl always comes out for my heavy multigrain bread recipe because of its additional capacity.
The Professional 5 Plus and the Professional HD from Sam’s and Costco are near clones of the 600, but I feel the tubular bowl handle on the 600 vs. the less comfortable strap handle on the other two makes the 600 more desirable than either of the five quarts. It also has a rubber handle on bowl lift that is a nice touch as well as the slightly higher capacity bowl.