Speaking as someone who has TIG-welded aluminum and steel and brazed steel, I would say it's a negligible difference in how skilled a welder needs to be if he's specializing in doing just that one thing day after day. As far as which one is stronger, I have no opinion on, but lugs are a good bit more aesthetically pleasing, and I've never really heard anyone **** a brick over the beauty of a TIG weld.

TIG welding Ti, on the other hand, takes some mad skillz, there are a lot of factors to take into account, like stainless steel, with it's weird heat displacement, only worse.