LH, in all fairness, may not be the most fancy J product out there as it is generally non-staggered 2-(2)-2 configured, but on the positive side is indeed one of the most consistent products out there. Regardless of the plane type, the seats will generally be the same - and service quality will be LH, I.e. in all likelihood not over the top servile, but professional, courteous and (to me) simply pleasant.
Thus, generally the type of plane will be less relevant than with carriers like UA that have varying configurations in operation.

Having said that, I like the privacy and stowage on the 748 upper deck a lot.
The 744 has the former first section nose seats with partial forward view going for it.
The 380 is a calm ride, but the cabin size is huge.
The 350 is pleasant without many specifics (screens being a bit better and headphones slightly inferior to other LH aircraft), but is said to offer the best cabin climate of all aircraft (though I appear to be quite insensitive to that). I do prefer it over 340 and 330 variants, though, if only for the novelty factor (and calmness).

I‘d look for the best schedule and price and then enjoy the trip as much as possible.