With CPS - have had varied experiences... really depending on the country where I've used it.
In some places.. super service with a loaner offered straight away when leaving bodies/lenses to be checked/fixed.
Elsewhere... been without a lens for 10 days as spare parts are being shipped from elsewhere in the world.
Also, have seen a reduction of the events that CPS have 'on site' service.. really has dropped down to almost nothing (or I cover the wrong sports ;-) )
Still.. guess there are some perks to it.. and it's not like being a member of CPS costs anything .. apart from all the gear you've spent money on.