Which is the best England & Wales Civil Registration Birth Index?

Ancestry has just updated its index to England and Wales births now claiming 71,311,303 entries from 1916 to 2007. For the prior period, from 1837, Ancestry has 62,793,107 entries making a total of 134,104,407 entries. Is it the most complete?

FreeBMD has 112,732,688, mostly complete to the early 1980s.
Findmypast has 124,866,012 entries to 2006.
MyHeritage claims 191,016,478 records in England & Wales, Birth Index, 1837-2005 and a separate database "England & Wales Births, GRO Indexes, 1911 - 1954" with 59,734,601 records.
The Genealogist claims "Complete Birth, Marriage & Death records index for England and Wales as published by the GRO (1837-2005)" without giving a number of births indexed.
FamilySearch's "England and Wales Birth Registration Index, 1837-2008" has 132,174,287 entries sourced from Findmypast in 2014!

I most often use FreeBMD as I prefer their search and presentation of results. The GRO itself has indexes to 1837-1918 births with extra information, but a more restrictive search which is invaluable for finding siblings in that period as the mother's maiden name is included as a  search option.