AFAIK, you can burn DVD+R/RW media with the older Superdrives -- just not through Apple's software. IIRC, Toast will do it, and the Finder will do it, but not iDVD, iTunes or DVD Studio Pro.
For reading only (not burning), the Superdrive will read just about any DVD media out there -- +R, -R, +RW, -RW, -RAM, etc.