Ultrakaz-HDCD encoded discs work on normal CD players-end of story.
I have recently changed to a HDCD dac,I already had about 2 dozen HDCD discs in my collection,they do sound better using the HDCD chip-a more 3d soundstage to be concise about it.
Craig CWOAGR does have a large HDCD logo on my booklet of that album but no mention on the case.
A reasonable amount of remastered and normal releases are released as HDCD discs but as they play on normal CD players it tends not to be overpromoted on the packaging-amongst those are Roxy Music, Van Halen,The Doors,Beck's last two albums,Mellencamp's new one,Natalie Merchant's last three,some Beach Boys and the complete Yes catalogue in Japan.
There is a healthy amount out there and they are very cheap here in the UK in a lot of cases,the Yes imports are expensive but that is unusual,with most other audiophile CD releases they tend to be more expensive than normal CD's
I can't compare HDCD to the other discs but it is a cost-effective way of getting very good sound reproduction with regards to both equipment and software.