In the January 2007 issue of Typotheque Ben Archer smacks-down Eric Gill and Gill Sans:
I contend that the majority of character shapes in Gill Sans are actually worse than in Johnston’s design of fifteen years previous.
This was an interesting read because I have never gone back to look at Edward Johnson’s original typeface. Ben provides a thorough analysis and I have a hard time disagreeing with his conclusions. I found Ben’s article via Stephen Coles’s Typographica where he recommends a couple of alternatives to Gill Sans including one of my favorites, Bliss.