I did have the MC601’s but I had them when I owned TAD CR-1 speakers. I never was crazy about those speakers and after trying amp, after amp, gear upon more gear, I finally gave up on them and sold them.
I have Sonus Faber Strads now. I fell in love with the Strads listening to them through a C500T and MC2301s. Ironically I never matched them up with McIntosh. I hope to in the near future. I have Ayre gear now with my Strads. A KXR-20 and MXR-20 monos. I still want/need to hear my Strads with McIntosh, so I am debating what to do/get.
I am like you and stream a lot. My system is playing 12-15 hours a day and a McIntosh tube preamp is not out of the question. The preamp tubes last a long time. I am sure the MX122 sounds great.
Congrats on your MC452. It’s a keeper. Get help moving the 452, it’s a beast.
Happy to help in any way possible.
Check this out for some audio porn.....http://audiokarma.org/forums/index.php?threads/mc452-on-the-way.699076/