I have one of each except the MFT/Kapex model.
They are all as stable as they need o be when using power tools such as the TS's, 850 planer, Routers, sanders and etc.
I have used the MFT/3 and MFT 1080 for hand planing, but only for the times when just a touch up or only a few light strokes are needed. I have a couple of solid wood benches that i use when planing with the armstrong powered tools. I even go to the wood benches when using a handsaw. I have used other MFT's that were mounted of solid cabinet type bases and those were quite adequate for hand work. I have avoided using either of the MFT's for working with any types of hammers. I suppose they are sold enough, but i like the solid feel of a wood bench when working with hammer and chisel.
I don't think the MFT's can be beat for assembly tables. There is an endless list of clamping methods with those tables, especially if using the Festoy clamps. I do avoid clamping anything that is heavy and might place a lot of weight on the center of the tables. I worry about starting the center to sag with excess weight centered over the middle. My 1080 and 800 are over ten years old and are still flat. My MFT/3 is only around 4 or 5 years old and does not have any sag. I have also avoided scoring the surfaces of the /3 and the 800. The 1080 is scarred all over the top. I need to be very careful when using that table for any glue ups. The glue gets into the saw kerfs and I have a problem. It can be difficult to scrape out of the kerf scars. I don't think it the greatest idea to try to remove glue with water, even if tried right away. The other two tables have both been treated with poly urethane and waxed, I have used protective strips when sawing over the tables and the surfaces are clean and unscarred. I have used both for many glue ups, spilled glue on them. They are clean and even if i don't catch drips of glue immediately, it is an easy job to flick it off the surface after it dries.
Tinker