In the naughties the quality from receivers was definitely sub-par vs. hifi separates when it came to pure musical playback. Or at least I found it so. HOWEVER, that may have had as much to do with speakers (yes, and cables) I could afford stateside to go with them,
Nowadays, however, the decent receivers seem to have decent DACs built into them and the audio quality should be on par with mid-price (i.e. up to 500 quid a box) hifi. The DACs are certainly better than those found in budget CD players, and of course, you are somewhat future proof for DTS audio. I currently have an Onkyo TX-NR717 which will "bi-amp" the front channel speakers using the front high level (as in altitude) channels which I don't want / use at present. It will play FLACs froma portable pocket sized 1 terabyte Western Digitial hard disk via the front USB, also from a PC or ethernet source. It should also do the same from the internerd, but I haven't worked that bit out yet. Internerd radio, BTW, may make all to talk about FM vs DAB redundant as both go the way of the BBC Home and Light Services. IMHO of course.
I'm using Klipsch RF-42 floorstanders, however, as the American indoors won't allow anything bigger and certainly not more expensive. It's apparent to me having tried using both the matching Onkyo Bluray and Onkyo CD player as sources, that the speakers might why the setup sounds weak playing pure music.
My advice, therefore, is audition receivers you like based mostly on audio. I would recommend listening to the Onkyo and Yamaha kit, but make sure you spend enough on speakers (yes, and cables). If you can, take along your favourite FLAC file(s) on a USB hard disk or pen / stick thing-ey as well as on CD.