Too many options, oh dear! :o Thank you again guys for your input. It is confusing, but very helpful! :) I am quite aware of the different options, but my main concern ist the "tonesuck"-issue of some devices. To have multiple devices is not an option, so a M13 AND a M9 is not on top of my list. And as I mentioned I play a JVM and will certainly not replace it with a modeller. I simply want a MFX with acceptable effect quality and the option to switch from "Clean Channel with nice Chorus and Reverb" to "Heavy Rock with Delay and whatsoever" with a SINGLE step. This is quite easy with both units HD 500X and PRO as both can switch channels of my Marshall via MIDI. But - coming back to where I started - I fear that additional gear and additional cables suck too much tone. I've seen so many posts in different forums saying "no way to get It work without loss of tone" on the other hand quite as much saying "no problem to set it up properly with a little tweaking". I used a GT8 (wrong company - I know) a couple of years ago only as FX in the loop, because it was not possible to set up the unit with 4CM without loosing lots of sound. This experience took me quite while and I have the hope, that a more advanced device lixe the 500X or the PRO would produce better results. Hope @PeterHamm is right with the cable issue...