Tried a few ships, and found a few important things to regard:
1. Cargo space - this one's a no-brainer
2. Room for Limpet controllers.
3. Maneuverability and speed.
I have tried mining in a T-10, Krait Phantom and Python. These ships can be regarded representative for similar ones. Personally I have found the Python to be the most useful one for my mining style:
- It has room for 192 tons of cargo. While not as much as larger ships, it's still enough to mine for 2-2,5 hours on end, which I find ideal, because I need a break after that amount anyway
- It has room for multiple limpet controllers. Mining with 5 active limpets is so much more satisfying than with 3 which I had in the Phantom.
- It is much more maneuverable than the T-10, which makes depositing the charges easier (and faster) and allows to fly between the cracked asteroid parts to scrape off the remaining chunks more easily.
- It is quite fast (almost 500 m/s), which considerably reduces the time to find the next core roid.
So anything bigger is too slow and cumbersome for my liking and anything smaller doesn't have enough internals for both, enough cargo space and enough limpet controllers.