Errr...
For a very in-depth answer...
Standard CDs have surfaces that consist of pits (reflect light) & lands (disperse light). Blank CD-Rs have all-land surfaces; when the CD-R is "burnt", the laser burns through some of the land areas to make pits. Also, the CD's Table Of Contents is written, telling any device that the CD is "closed".
A CD-RW's recording surface consists of a special crystalline substance that when heated (i.e. recorded to) becomes solid, and mimics the pits/lands of a standard CD; when the CD is erased, the crystal is heated further, and "melts" back into its normal state (lands). In other words, its reflective properties differ from standard CD-Rs, and devices that can read CD-RWs have slightly different lasers (reflect light differently).
Additionally, since a CD-RW is not completely written to (never can be) and is never closed (CD-RW TOCs are different to CD-R TOCs), it *cannot* be read be standard CD-ROM drives (i.e. the PSX's), which will always look for a "closed" (CD-R *only*) TOC.
Interesting what you learn
Bck to topic, tho... yeah, an ISO would probably be your best option.