Depends how much you rely on your Mac, and how annoying random application bugs may be.
Do you have time to waste chasing down problems if they occur? Is it (the potential for bugs and maybe stability issues, data corruption if you're unlucky, inability to restore your data into a non-beta machine, etc.) worth it to you to have the new features a couple of months early?
Only you can answer that.
I've run betas many times in the past and whilst the novelty to see what is coming is nice, as far as getting work done goes it just gets in the way. Some apps may stop working, in a couple of the betas for previous OS X versions i had wifi flakiness, bonjour issues, etc.
Personally: I'm waiting.
Betas are more useful if you're a developer, to get your software ready for the new platform. If you're an end user... only you can really answer if it's worth the hassle.