I like both, and not necessarily one more than the other, so I did not vote.

ARFs
If I want something soon
If I want to save money
If what I want is only available as ARF

Kits
If I want to take my time
If not available as ARF
If I'm in a "building" mood

I have noticed that crashing an ARF bothers me less than crashing a kit built model. The only attachment to the ARF is the money. A kit built has the money plus the time, so it hurts more when it breaks.