If you drive it alot, turbo (intercooled, of course) is the way to go.
If it's just a cruiser (i.e. <10k miles a year) I see no compelling reason to undo what you've already got money invested in. Both accomplish the same feat through different means.

Turbos are harder to "package" due to the piping for the intercooler, location of the intercooler and the physical attachment to the header(s).

Just my $.02 and you know I'm biased toward turbos!