I do find all the variations interesting and wonder which one will finally shake out to a “standard”.
We have the tool changers like the XL, U1, this Flashforge.
We have the nozzle changers like the H2C, the new Atomform.
And the INDX which is a little bit of both.
All have pluses and minuses. The complete tool changers are a lot more complex, and have a lot more parts to fail, and are limited by space. But if a tool head fails you can print with the other tool heads (if firmware allows).
The nozzle changers are less complex (but look more complex). They are slower (for now), but offer more colors/materials over dedicated tool heads. I think the buffer system shown by AtomForm will be copied by Bambu (though Bambu kind of has it already in the A1) They also offer a lot of flexibility in terms of changing up nozzle sizes very easily, and ability to have a lot more tool heads in a smaller space. If the tool head fails you’re down, though.
The INDX has a blend of all pluses and minuses. But it can fit far more nozzles in less space than the other designs. I really hope the Sovol machine is an INDX machine, and that it fits in the space I have lol.
Ultimately, multicolor printings biggest flaw is $$$. With two 4-slot AMS units and one HT AMS, my H2C can print 9 colors at once. At ~$15 per roll that’s $135 in filament just to print a model in 9 colors.
Or, I could print in single color and paint it with $10 worth of paint. Which is still the best solution. As such, I mainly use one color and the right nozzle has support material for full contact support. The AMS units have a variety of materials.