Truthfully I don't know, I don't even have an A class freighter. I suppose it depends on how you like to play. If freighters are important to your experience I can imagine someone wanting to eke out as much storage and stats as possible.
For me, its the aesthetic look of a freighter first just so I can see it hovering over my base. I'd be happy with one of the big ones which look like a Star Destroyer or Sulaco-esque.