Compression connections are not approved for use in concealed locations in many parts of the country.
What PEX manufacturer recommends to use compression fittings instead of crimp or other connections such as Wirsbo propex or Rehau everlock on their PEX tubing?
Compression connections have their use in a plumbing system, but to install a complete water distribution system using compression fittings would not only be unwize and asking for potential leaks but be against code in many places.
EDIT: Oh yeah, I almost forgot about the ever popular FlexPex system with Flair-it fittings. Its 2 - 10 yr. warranty really competes with the 25yr warranty of other systems too.