The MXT has two bellows. The upper one, between the light source and negative stage only really comes in to play with the condensor head. Diffuser heads use the collapsed position. So issues with that section are minor. The lower bellows, film to lens, is used partially extended all the time, so light leaks are an issue
Negative holders are necessary. Lens panels are easily made, and enlarger lenses should be easily sourced.
Transport: Try to do it upright (take the head off) to keep the system on its tracks. You can unscrew the base board (have a container for the screws) if you want to reduce the weight.
Beselers are not 'native' to Europe/Scandinavia, so parts may have to be sourced internationally.
Do you intend using it for 4x5, roll film, or 35mm? If 4x5 is not on your horizon, something smaller might be a better choice.
The MXT is motorized. Check that it is correctly wired and suitable for your voltage. And make sure the motor works. Operating the head without power is not easy.
The manual says the shipping dimensions (unassembled) are 1,270 x 737 x 432mm, but the unit assembled without the head is 1,143mm high (just measured mine). All up weight around 25 kg.
'Color head' may just mean the condenser head has a filter drawer, or it might be a Dichro 45s or similar.
Value is really what you are prepared to pay for it, based on your need, what alternatives are available, and if you feel that you can fix any issues. (never mind if the seller says something is an easy fix - they have not done it, and they will not be doing it!).