Like some of the comments above indicate, I personally think that the preamp sections of modern mid-to-high-end Av receivers are pretty good with decent DACs and most of us are using their digital inputs anyway. (I can't say the same about the analogue inputs, from experience with my own AVR).
However for music, in my opinion, where AV receivers fall down and/or differ greatly is their power/current delivery and room-correction software. That's certainly the case with my own amp. I actually like the musicality as such, but it's not as capable at controlling the bass as my previous integrated amp, despite it's significantly higher power ratings. (But we all know about AVR's power ratings!)
With many mid-to-high-end AV receivers running 9 or 11 channels, ultimately their power and grip of bass for two channels is limited. This can be solved by either running a separate power amp for your front left & right channels, or the AV direct input of a suitably-equipped integrated amplifier. Personally I'm inclined to consider the power amp for simplicity-of-use's sake. Also it means you can have a mid-priced AVR with a decent power amp. AV receivers are outdated quite quickly, so buying a high-end AVR in my opinion is a fool's game unless you buy a highly discounted previous year's model. Otherwise you're just losing wads of money with depreciation considering their useful life. At least if you had a decent power amp, you could keep that for many years, just replacing the mid-priced AVR when all the formats make it obsolete.
But the other primary area that AVR's differ is their room-correction software. And Arcam and Anthem really do lead the way here.
Personally, spec and price-wise, I'd be really interested in a Marantz SR7011 maybe adding a decent power amp in time, but the thing that does hold me back a little with this option is the Audyssey's room-correction software which I don't think is anywhere as effective as Anthem and Arcam's alternatives. Actually Anthem and Arcam's room correction software offers some users (if you had a really acoustically unhelpful room) significant benefits over an integrated amp.
So I think in the meantime I'm just going to have to save my pennies and wait for an Arcam AVR550 when it's discounted and about to be replaced! Or maybe an AVR390 and adding a power amp? So many options!!! But for you, much might depend on how good or bad your room it acoustically. If you don't suffer bad reflections and bass nodes (like my room does), then you may feel that room correction is not as critical for you. In which case, it's hard to argue with the Marantz SR7011 at the moment for about £900. Quite a lot of ability for the money, particularly when you consider you'd easily pay half that just for a streamer that had all the features it has.