Both but mostly contracts. My choice is limited here since I still suck in escort jobs. It boils down to either killing up to 12 enemies or an ace fighter with his gang. It's a big difference though "where" I take these contracts. From my own station 12 enemies would be an isolated task. Meanwhile I found a strategy that is almost risk free, just need some (read: a lot) patience and time, in other words: a little boring. In Tranquil, where I bought me into the orbital station (for 12 Million, one of the reasons why I'm such a poor churchmouse), all fights take place in orbital range with all kinds of random enemies but also allies, including battle ships, cruisers and trading ships which is quite *interesting*. Here I usually prefer to go wild (and die often but have some fun

)

And here I train the basics of switching between IDS and inertia mode which isn't necessary with the other method.
My main problem seems to be that miners are noticeable underpopulated in Pearl, their contracts are rare and not efficient, reputationwise. Even if bribing would work in the long run (I'll try with more but lower fees) it's just not easy to meet one.
Edit: To be more specific to your question Paul, amount of kills [edit: needed for reputation gain] out of contract seems enormous, didn't count though. Killing by contracts gives basically 1% per contract if its for Navy. For Miners it's much worse, something around 1% for 3 contracts and even less when the amounts of enemies are low (like 5 or 6, so it appears to me at least). Again, this is only true for this certain situation in Pearl.
[Edited on 9-4-2014 by picommander]
Edit: accidental quoting tags removed
[Edited on 9-4-2014 by picommander]