To me the front tuck seems likely to be easier to do cleanly, since there's no bent knee deductions, but it really will vary depending on the athlete.
(Personally, I don't like aerials in general, more for developmental reasons than for scoring ones. They are, for the most part, a developmental dead end. They can perhaps be used on beam at higher levels, but that's about it. A front tuck, on the other hand, is an essential step towards a ton of other skills)