From the limited research I did before buying my DVD Standard, it seems the SACD is marginally better, but to me, the reliability issues with the SACD transport put me off.
Like you, I also looked into the 280CD, but couldn't audition one locally. Again, from what I read, it seems the 280CD is more along the lines of the DVD Standard, but not as refined as the SACD.
In my system, I'm using Quattro Fil XLR running balanced into a KAV-400xi and Red Dawn RevII for my Focal Utopia Micro's. I also use Nordost power cords and I'm really happy with the way my system sounds.
I have been really happy with redbook playback on the DVD Standard. You must run it balanced to get the most from it. Power conditioning helped as well.