Well, there's no real dates yet, so 17. May is just a guess since this is the same as seti@home's 5-year-anniversary from official launch.
The resent inclusion of stackwalker have made the debugging much easier. The alpha-team does "burn-in" tests of clients & helps filtering out noise from the beta-board and report the real problems back to developers.
In the beta it's a 2-week-delay from client-release to actually enough has switched to know if a bug is fixed or not...
The last couple of months the error-rate has decreased from 17% to 10%, so it's progressing in the right direction.

The next beta-release should be Friday or Saturday if no serious bugs pops up in the current alpha-testing, and will contain debug-code. Depending on the error-rate, maybe the debugging can be turned off for the release after that...
Any wu not crunched in seti@home can be crunched by BOINC, so there's nothing lost by terminating the current seti@home-clients then BOINC is stable enough for release.