Public beta next week, developer beta 2 in 40 minutes I think.
The reason the Public Beta lags behind the Dev Beta is generally to hold off in case there's any major show stopping type bugs. Once any issues with the Dev Beta are fixed, that's what's usually released as the Public Beta, and why they usually have the same build number. Considering how stable beta 1 was, and if beta 2 sticks to that form, I'd assume a public beta this week. Maybe even as soon as tomorrow.