In my opinion, on-the-fly 2D to 3D conversion isn't such a great experience and gives viewers the wrong idea on how good 3D can be - so go with the native 3D content, if possible.
N'uche nke m, na-ada 2D ka ntụgharị atọ ọ bụghị ụdị ahụmahụ dị oke mkpa ma nye ndị na-ekiri echiche na-ezighi ezi banyere otú 3D nwere ike isi bụrụ - ya mere na-aga na ọdịnaya 3D, ma ọ bụrụ na o kwere omume.