Just thought I'd share my experiences (another one) with regards to this little mini system. I've come from a slightly different direction and have undertaken a simple upgrade that other owners might find useful.
I've always loved my hifi and due to kids and no space had to box up and pack away my beloved system, a CD based system circa £14k although I have another £7-8k of gear "lying around" lol. Anyway as I said don't now have the room to set this up and wouldn't really want my 4 and 7 year old playing about with all that equipment and they do love their music!
So I read up on the current crop of mini systems and went for the Marantz as I thought for the money it was a no brainer and I wouldn't worry about the kids loading a CD. It looks quite stylish too and one box and few wires so the wife is happy too.
Anyway I tried my current crop of speakers - Proac super tablettes, Proac response 1s and Sonus Fabers (ranging from £5-600 for the little tablettes to £3k for the SF's). I always loved the midrange and imaging of the super tablettes and of the 3 speakers this is what I went for. I have a couple of REL subs so one will provide the bass missing from the Proac's.
I also had slate and granite slabs epsecially cut for my other system so tried a 2" thick granite slap with the Marantz - and even for such a "cheap" piece of equipment it had a marked effect, firming up the mid and lower bass and just generally improving the sound of the Marantz - maybe something others might want to try?
I can also report that although you couldn't directly compare the Marantz with my other system its a fun, great sounding little piece of equipment. I will eventually set up my other system but am thoroughly enjoying the Marantz although a compromise I didn't expect such good results.