These are all ships that I've personally explored in, I look at exploration ships overall, jump range, how they handle in supercruise, how they handle on planet surfaces, how well they handle Exobiology. I also tend to use ships for shorter range exploration, I'm not taking these out for 6 months at a time.
S-Tier
These ships have a great jump range when engineered, they have a small footprint so they can land almost anywhere, but still have enough space to fit everything needed to explore. They're also pretty fast and snappy in real space as well.
A-Tier
Great jump range, good space for all that you need to explore but harder to land, not great speed and slower to turn in supercruise but great otherwise.
B-Tier
Decent jump range but need engineering and FSD boosters, however, they are very fast and are great for exobiology, also people think you're crazy when you go exploring in it, but you show them :)
C-Tier
Great jump range but need to be stripped down to make use of it, adding an SRV alone cuts off several light years
F-Tier
It's an adder, it can do okay but is just average
