I was going to suggest the Raumfeld, but I have done quite a lot, and I have nothing to reference it against. I will say I think it sounds great, but I suppose I can 100% recommend it due the fact you have an 8 week trial if you buy it.
I am probably not astute enough to notice the delicate difference between a system that's good or bad for heavy music, but Pantera and Metallica sound good to me from this unit.
It's dnla compatible, spotify connected, tune in radio, and something I particularly like is you can rip albums and copy them to a USB and play direct from the app, flac or other formats. It has RCA out and optical if you got a better DAC. I'm surprised after buying one that it's not a more popular unit
Oh, in hifi terms it's inexpensive