Was the Correlation Estimator block recently added? If so, thank you whoever wrote it. If not, thanks anyway. It seems to be an alternative to the infamous Corr_and_Sync block.
I also like the testbench that goes with it in gr-digital/examples/demod. I did not know I could use Modulate Vector (or the existence thereof) to pre-modulate a preamble. Very clean.
Just some positive feedback.