I will speak to the MHA50 DAC/ Amp for headphones. Answer is absolutely not. There are much better options. Why?
1. Dual DAC isn't always better, but in this case you can immediately tell the single DAC doesn't provide the staging required for the beauty of something like Grado cans. It's there, but not on par w/ the quality of the headphones.
2. The connector tolerances are poor, and others have complained that their 3.5mm jack doesn't fit right. My microUSB jack never fit right, and I had to tape wires and stabilize the unit to get a connection. Very poor for $750.
3. My unit's battery expanded and cracked the glass cover, breaking the touch-sensitive volume control I already hated. Now it doesn't work, and cold-start levels aren't usable. See above - so now it's taped and rubber-banded together but barely emits any sound (in hard to drive cans) so it's useless. Though I wouldn't toy with a defective battery, and this may be charging logic as I kept my connected for ...a year straight (listening 12+ hours/ day at work believe it or not).
4. Service - it wasn't the $300 they wanted to repair my unit, it was the attitude. I have other McIntosh gear and it's solid, but the principle was enough to drive me away. I'll shop other vendors henceforth.
McIntosh power is hard to match. Their amplifiers are absolute in this regard, though the definition, staging, front/ back (usually back-ish) and shape aren't for everyone. You do have to match speakers fairly closely, IMHO, and I had a nice match (old Cantons made in W. Germany, that's how old - and an old non-tube amp) so it was nice, but the mids sounded somewhat pronounced and over-pushed, despite being back in the staging. The low-end power, bass, smoothness, tightness...that's classic McIntosh to me so wire up a monoblock to a sub and go that route, then find something with the finesse you want from the speakers you prefer. It may not be a McIntosh...speakers first, then amp IMHO.
But avoid the MHA50 unless you want to start a fire or replace the battery after a year of use - for almost half the cost of the unit (and surely a 12-week turnaround - no priority for a cheap unit for sure).