As already stated, it depends what you're after.

My experience has told me, when building for competition, it's easier to build from scratch than from a kit. The thing is, that every aircraft is unique in many ways (and has her own personality). Do your research first and decide on a particular instance of an aircraft (not just a type) and go from there. Document first, then build. It's far easier to plan than to retrofit. You may be surprised how many modifications are made after the original drawings were done.