Not much difference because of HDCD. Not many titles are available in hdcd format. Some receivers (many denons) can also decode hdcd removing the need for the cd player to decode the format. IMHO, seems like sacd has a lot more press and hope for becoming the main stream hi res format.
If by chance you really wanted an HDCD album available only in that format, it is backwards compatible with non hdcd equipment.
There are probably some other differences for $300 that don't apply hdcd answer. I don't know what they are..