#2 has too much filter effect & not practical for print branding.
#3 The icon has been used for several other generic logo's (Not original)
#1 clean but the overlap with no separation lines would complicate it in a black-n-white print environment.
#4 Was my favorite, clean, simple, printable in color & black-n-white, usable for the web, just all around flexible for branding a business.