Novices will have loads of fun with the ring modulator. That's the robot voice effect, in that it turns everything into a robot voice. Time stretch makes it possible to lengthen or shorten a sampled phrase in real-time without changing its pitch. Actually, that's up to you. Because of the limited built-in memory, you can control how much of the memory is allocated to one sample by selecting the sound quality.
Low quality equals little memory, high quality equals much memory.
The difference is actually quite noticeable among the four different grades available. The low fidelity rate can sound really cool if you tweak it. The highest rate sound very good. At the lowest quality, DS can handle up to 4.5 minutes, something like 37 minutes with the SmartMedia expansion card. Also, each sample can be stored at a different quality, so some sound clear as bells, some dirty as could be.