I have one (VR-507), I used it with 2 pairs of main speakers now:
JBL Northridge N26 Infinity Alpha 20 (bi-wired)
The sound is definitely tinny (tin-can sound), leaning more towards neutral than bright, definitely not warm. No real depth either but you get what you pay for. It does get loud without much clarity problems though.
On the A/V receiver side it's pretty darn good. Only problem as of late is it stops responding to the remote 60% of the time. This happened over the course of 1.5 years but this past summer it's been really horrible.
We have an older Kenwood HTB upstairs (VR-407? receiver) that does the same thing and I did some Googling on the subject, others have had the same prob. Hopefully the newer models have a more reliable IR sensor.
That sounds like the model I had or close to it. Its long gone now and I don't remember the model #. It had DD but not DTS. My volume on the remote quit working as well but luckily it was still under warranty. The sound was just as you described tinny but played very loud and clear. My tower mains with 10" woofers sounded like the woofers were unhooked. I thought for a long time that the Kenwood mains just sucked until I upgraded to the Onkyo that I have now. Running the Kenwood receiver without a sub is definitely not an option.