Those are two very different questions.
For the time being, if those don't have an MQA DAC and care about some level of MQA unfolding have to use the Tidal desktop player. MQA software unfolding is coming to Roon though, so this situation is just temporary for Roon enthusiasts.
Of course, depending on your use, Roon has many advantages over Tidal desktop player, including:
- Remote control via Roon Remote
- Enriched Metadata
- DSP and Convolution (for digital room correction)
- Distributed architecture - Roon Server does the heavy lifting while Roon Bridge streams to your DAC
- Streaming to Roon Ready and SONOS network players
I'm sure that I've left some out, but you get the idea.
The question about ripped CDs vs. streaming MQA from TIDAL is more difficult to answer in general. I've discovered that more often than not, mastering quality trumps distribution format. So, the fact that an album is available in MQA does not guarantee that it's the best sounding master. I know that we all wish that it did, and there are many excellent sounding MQA albums on TIDAL. However, MQA stands for "Master Quality Authenticated" not "Mastering Quality guarAnteed." We know that the bits have not been tampered with since they left the studio, but we don't know if they were any good to begin with!
For example, I have a number of XRCD, DCC, and MoFi CD rips that do sound better than MQA or high-rez downloads from HDtracks, etc. in spite of the fact that they are only 16bits, 44.1kHz. I imagine they could sound slightly better with higher resolution encoding from the source, but the sound quality comes from the excellent mastering (or re-mastering) work rather than the delivery format.
Don't forget that Roon does a beautiful job of integrating your local FLAC library with what's available on TIDAL. When there are duplicates, it does a fairly good job of selecting the best version, but you can always override its choices.