I would pass on Yamaha bellow 685 model because all of the lower models do not have counterweights and/or graded keys.
? pretty much all pianos have 'graded' keys. The only difference with the 675/685 is that each key is graded rather than in the 4 or so zones that most pianos have. It's not really a difference anyone notices in playing though, also I'm not even sure if yamaha actually do it realistically or simply have it getting lighter note by note in a smooth fashion. An acoustic doesn't actually have a smooth change in weight as while the hammers get lighter bit by bit as the notes get higher, the counter and damper weighting along with any springs involved are typically done on a zone by zone basis (and of course the further disconnect in the top octave and a bit where there are no dampers).
Also I'd hesitate to put too much value in 'counterweights' alone. At best they imply a larger dynamic weighting compared against a non counterweighted model from the same range. Comparing across manufacturers is a little pointless though, an otherwise very light key with what is nominally a counterweight embedded in it might still be overall lighter than a competitors key which is simply got more mass to it.
Ultimately it's personal preference, since VMK has been playing acoustic for many years they probably have a pretty good idea of what they consider to be a good feel based on the acoustic(s) they play on which, of course, vary wildly.
Not sure what prices in Armenia are like but in the UK the kawai competitors in this range seem to be the CN37 (bit less money) and the CA48 (bit more money) with the slightly puzzling situation where the former has a better sound engine but the latter has a (probably) better action.
I think the HP603 is the least-expensive "console" Roland with their best action and SuperNatural Modelled sound generator.
Possibly not for much longer I think. In the UK the 603 seems to be in clearance sale mode and looks like it's being replaced in the line up by the 601 which still has the pha-50 action but the previous sampled attack/modelled rest hybrid supernatural sound engine