I have always heard that Metal Slug on CD was a great version and in some ways even better than the cart. I happen to have the MVS and, of course, love it, but would ove to see the extra goodies on the CD
Also, the remix music on Real Bout is just fantastic. The loads are, of course, a little annoying, but not nearly as bad as say a KoF or later Sam Sho. AsS far as graphically, the only thing missing is the fire truck in the "Billy/Yamazaki" waterfront stage.
In fact, when I sold my CDZ, I made a burn of the Real Bout game CD so I had a copy of the music, I liked it so much.