I'm running gqrx with an RSP1A on Linux, so I can only comment on the program itself (features, GUI etc.), not the installation process, but it's basically the same situation on Linux as on MAC: You have only two choices, gqrx or cubicsdr.
I also tried cubicsdr, it's nice but when I tried, it was missing a real CW mode, and since I'm an old fashioned CW operator, that was a major problem. At that time, the RSP1 integration was better than in gqrx, but nowadays gqrx is supporting the RSP1(A) just fine. Don't know about the others.
Gqrx is quite minimalistic, but has exactly the features I want for amateur radio. And the features I missed or didn't like the way they were implemented I have added or modified to my needs, so for me it's nearly perfect now.
I installed SDRUno with an RSP1 on the Windows PC at our club station. It's a very nice program with a lots of features, but since it is more of a general purpose program not optimized for amateur radio, it's missing some of the features I have with gqrx at home, and the transceiver control is far behind my implementation with gqrx. But is has the best RSP support, and when SDRPlay brings a new hardware, you can expect an SDRUno version with good support at the same time. That's great!
I also installed HDSDR on the club PC. RSP1 ist supported very well, I don't know about the RSP2 and RSPDuo. HDSDR's user interface is closer to gqrx and transceiver control was working better than with SDRUno, so for amateur radio I prefer it over SDRUno.
That's my (quite long) 0.02€.
Reason: No reason