The only reason for buying the compete is the price, which may or not even be the outcome depending on replacement parts, good deals, pre-owned stuff, etc... There is no other reason, every other option favours the build from scratch. Which obviously goes for the Surly frame itself, cheapness is the only reason.

Speaking of the complete, before it became available, and to some extent since, there was a thread a week on this subject, and none of the parts have really changeed much since. So do a search in addition to what you get back here.

I would also look at the Bruce Gordon frame, and his build kit deal, if for no other reason than that it represents one take.