Board Thread:Game Discussion/@comment-1964873-20130505020247/@comment-8284783-20130509002340

If you want to farm for upgrade fodder, the best mission would actually be 2.1.3. Not only does it have the highest average credits value for the "regular" cards (all R2s), but the rare is also almost decent (worth 910 credits), which is much better than Cyclonus (considering he's the worst rare, that's not too hard to beat :P).

If you want to get some more weapons, instead, then 2.3.4 would be your best bet. Again, best average value of normal cards, and a rare weapon (they are all worth the same, so the only thing that changes is how much the other cards will be worth, on average).

These are all decepticon missions, I haven't had time to check out all the autobot missions yet.