Clayne said it right. Why Hermes MP, why not "plain" MP? As much as new Hermes is more expensive than "plain" MP, that much secondhand is too. Or not, secondhand could be even more expensive as those are made as clayne sad for collectors, and add nothing to functionality. I am sure that for price of secondhand Hermes for example 5 years old MP you can buy regular 2 years old MP, send it in Solms to CLA, checking and repairing if something need to be repaired, all that for price of Hermes. Don't forget, when buying secondhand RF cameras it is good practice to send it to CLA. SLR you may or may not, but RF should be sent to CLA. And, that cost a bit if it is done at authorized place. Add that cost to price of camera and Hermes by mine opinion is not reasonable decision if you are interested only in functional Leica. If you are interested in looks of camera and/or status as much as in functionality, then buy Hermes. In fact, if you can afford, buy new Hermes. But if you just manage to get money for secondhand Leica, then regular, younger, CLA'd and checked/repired MP by mine opinion is better choice.

And, wouldn't be better to buy regular MP, add a little and to buy another (Leica) lens instead of Hermes?

Whatever you decide, good luck.