I have found that there is a bit of difference between the medium haul flights (4-6 hrs) and the longer haul (10+ hours) ones.
The lounge haul ones have significantly more food in service, in addition to a selection of appetizers off the cart. The medium haul ones tend to expedite the service through a few smaller courses.
Amenity kits are also smaller on the medium haul flights - even on the wide bodies.
I've had bad luck trying to contact THY for issues. Emails are mostly unanswered. Seat assignments (only available 100 days out or so) don't always stick. If this is important, I'd fly elsewhere.