I rarely put on a complete set. I almost always mix the basses and trebles. This isn't necessarily because of a glaring mismatch, but I often prefer the basses of one set and the trebles of another. A buddy of mine purchased a set of Augustine blue basses paired with classic trebles... high tension basses with low tension trebles, which just seemed like a weird match to me.
In the end guitar strings are highly personal and what seems like a mismatch to one is a match made in heaven to another. It depends on the player preference and how the individual guitar responds to the that set of strings. This is why I appreciate how Strings by Mail allows for mix and matching bass/treble sets and even individual strings.
"Success grants its rewards to a few, but is the dream of the multitudes.
Excellence is available to all, but is accepted only by a few." - Christopher Parkening