I have tried flying them, I've used 8 of them and only noticed slight nearly negligible differences in handling and such. IMO it's the devs attempt at balancing every faction, inadvertently that have made it severely over balanced, thus killing much of the mod realism.
BTW, it's not that I don't like the mod, Discovery remains one of my favorite mods by far. I just don't like the lack of realism, and how stoic the mod feels. It seems whenever I play on the official RP server the VAST majority of people are in capital ships, and 90% of those who aren't only aren't because they don't have the money for one yet. Tell me, how is that true RP? It's not, it makes no sense. And why does everyone get a capital ship eventually? Because VHFs/SHFs become almost useless eventually, players can have a VHF with all class 9 and class 10 weapons, the best scanner, and a class 10 shield in just a few hours. Then what do they do with all the rest of the money they get? If they want to spend it on themselves their ONLY option is a capital ship, I'm just asking that they add other options for those of us that has no interest in capital ships whatsoever.