Looking at the A-S500, R-S500, RS300

I'm looking at getting one of the new Yamaha amps. Being in Canada finding these ones isn't easy. I've only found a couple of dealers that stock them.

I wouldn't mind having the built in tuner, and getting a quality antenna to hopefully pull in some different stations.

The AS500 $499 CAD.
Another dealer has the RS500 for $350 CAD.

I'm not a crank it up kind of guy and will have 1, maybe 2 tape decks, cd player and of course a turntable.

I'll have HPM100's, Advent large, or Dynaco A25's to use with it. Any input is appreciated. Hard to beat the $350 for the RS.

You won't go wrong either way. They'll both sound great; it's really a matter of want you want your system to do and if you want the built in tuner. I love the A-S500; I haven't heard the R-S500 but Yamaha is very consistent sounding.
The new A-S501 has coaxial and optical inputs as well now so it is even more versatile than the 500. You can stream music from a Bluetooth device to the 501 with their optional yba-11 wireless audio receiver. I wouldn't mind having the 501 over the 500 for that alone; otherwise they're the same.