I'm going to say Beta 5 today and RC1 next week, there's been quite a few bugs reported/fixed between Beta 4 and now, so I'll assume they'll want a little more testing.
On the other hand, if there's another Beta, we all know some people aren't going to be satisfied and we'll have at least 1 thread with "zOMG! Another Beta? Just shows how unstable XF is! I'm thinking of selling my license and going to IPB" and then... we all know they'll be here next week, still owning their license and posting for help

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