I'd probably use RunRev before I used something like RealBasic, which is basically in the same market - small, 'soup-to-nuts' shareware developers who want to create desktop apps with multimedia, internet, and database capabilities. Heck, I'd use it before I used Authorware or even some of the Python tools in that general domain (PyCard, etc.) because it was faster to develop and you put out a more polished product, without cross-platform woes. The MetaCard kernel engine is actually pretty fast, execution speed-wise. It could handily beat Perl for some stuff that you wouldn't think it would even be useful for...we scripted a performance testing tool and a utility to put database records into HTML, and it trounced Perl for both tasks. Which was impressive, considering Perl would have sucked at making cross-platform multimedia apps ;-)
I almost invested in RunRev when they were first getting started...IIRC, Mike Markkula (Apple fame) did invest in them. The founder, Kevin, is pretty cool. I ended up just becoming a customer and using it as a prototyping tool. I still have an older Pro license and a couple books about RR if anyone is interested...
Anyone remember GLPro? That was another niche app we used to make prototypes and build small multimedia apps and screensavers. It had a dBase style engine in it? We used it for a screensaver once and it ended up on an episode of Star Trek Next Generation. Or iShell? That was a later one we used that was based on another defunct Apple tool. It's still around, I think. Even with the huge range of software available today, I miss working with the little, niche multimedia and audio development tools. Those are what got me into programming.