As I said at http://news.ycombinator.com/item?id=656493, I don't see why the communities for other dynamic languages are still investing so much effort into building new VMs instead of collaborating on something like this.
I too, really like the idea of a single VM for many languages. Having just watched the Google IO video on V8, I'm starting to think there are some serious advantages to specialized engines.
For example, V8 replaced the regular expression engine that Webkit was using with one that was specially designed to work with Javascript's regex syntax. Maybe you can get similar performance with a generalized engine, but I'm no longer of the mind that one VM for all languages will be the end-all-be-all solution.
If it just makes implementing languages with decent performance and good GC easier, then it has benefited us tremendously. If it can additionally free a language developer from the hurdle of "there's not that many libraries yet" then this is also a good thing.
