FrankHarveyHiFi:
As HCC mentions, this will depend on the speakers being used, the room etc. But it will also be down to the individuals idea of 'musical'. Looking at it from a critical point of view, the answer is the Arcam. But to many, a DSPZ7 would fit the bill, or even something between £500/1,000. It's all down to what you're used to.
Musically, without going down the pre/power route, the AVR600 would be the first choice for an AV amp that has to double up as the heart of a hi-fi system as well as an AV system. It's ability to drive awkward loads is pretty amazing for it's price point, and is one of the few amplifiers that can drive a speaker package well above that that should be physically possible. I've not heard the comparison, but the rep claims tha amplification of the AVR600 outperforms their P7 power amplifier.
It may have good quality amplification, but it doesn't do as good a job decoding stereo music as my DacMagic (mooded with Burson opamps). With the Arcam decoding stereo music, the sound is detailed but seems to lack what most AV amps suffer from, a lack of depth and realism to the midrange, it just sounds a bit frail. The modded DacMagic (total cost = £385) solved that problem for me.
It's probably also worth pointing out that the AVR600 still seems to have a few bugs to be ironed out. I've got the most recent 1.8 firmware, but still lose audio if switching between sources, either having to switch the power off or change channels on my V+ to get it back. Also, the speaker pops are still around when turning off and switching sources. Hopefully these will be rectified soon when 1.9 gets released, but perhaps faults this extreme should have be sorted before release on such a pricey product.