Tell me your feelings on the visiting lecturer gig

Though I've totally come to terms with the very likely possibility that I won't get a TT position this year, I continue to search the job boards, albeit with markedly less fervor.  Maybe once a week.  Recently, I've seen a couple of ads for one- or two-year non-tenure track teaching positions at solid-to-excellent liberal arts schools, and I'm just wondering, is this kind of thing a good idea?  For anyone?

Naturally, it would look nice on my CV if the places I apply to in the future value teaching experience.  But I'd imagine it takes at least a year or three (or +++ ???) of teaching any given course to really tighten the screws, so wouldn't I expect my first year evaluations to be sort of, well, bad-ish?  And what is the point of a university investing in a teacher who won't be around long enough to get the course to the awesome level?

Also, since it's a limited engagement, I'd have to spend a good amount of time during that year applying for jobs for the following year, which could take a non-trivial amount of time away from planning 4 courses per semester, no?  And speaking of future positions, I'm wondering what taking a year off from lab work looks like to hiring committees at research-heavy institutions.  Obviously, it's a year with no new publications, which I worry may not be compensated for by the boost in teaching experience. Or will it?

So let's hear it--are there worthwhile benefits to the 1-year teaching position for someone still interested in doing research long-term?