A Yamaha DGX 200 for 600 CDN is not worth it at all, IMO. First off, if this is for someone who wants to learn or play the piano, in a relatively realistic fashion, the PX100 is leaps and bounds ahead of the DGX200 because it has 88-weighted hammer-action keys. The DGX200 does not. What that means is, the feel of the PX100 simulates that of an acoustic piano, while all the keys on the DGX feel the same.
However, if you're looking for something just to mess around with which has a lot of voices and features, then the DGX has the clear advantage. But, with the exhange rate being so low between US and Canadian dollars you can buy a DGX200 off a US online retailer for about 240US ( this translates into about 295CDN ), and pay for the shipping and tax. The total will be much less than the quoted 600 dollars.
So if you're looking for an entry level synth( keyboard with lots of voices and features) the DGX is a better choice. However, if you want a digital piano( concentrates on realistic keyboard action and piano sound) then the PX100 is the clear winner. Happy Shopping!