Dragons and Balrogs

One more point on the subject. In The Silmarillion, it happens to mention that, of all the creatures of evil, it was only dragons that Sauron could not control. Hell, that sounds like dragons are pretty damn powerful to me. And if he himself could not control them, there is some allusion to the possibility that they were immune to the insinuations of the Ruling Ring, which is most definately saying something.
Of course, since dragons have that bit of magpie urge of theirs, they might have taken it anyway if they'd found it.
Another thing, I wonder- could dragons pick and choose their alligiences? In one of the Lost Tales, Farmer Giles of Ham, the green dragon Chrysophylax becomes friends with a mere, rather puny, human farmer (or as much of a friend as a dragon could make himself), and, in outlining for future stories (which were never written) mentions this green dragon protecting and even rescuing him, which are qualities one would assign to more benevolent creatures.
In the words of a friend, following this question:
"Well, some are better or worse than others."
Makes you think....

[Eomer of the Rohirrim]

I know the topic is specifically about who was greater, but its still interesting to talk about who was more evil.

The point that Sauron was not able to completely control the Dragons suggests that they were more independent than the Balrogs with regards to their choices. Now, if the Balrog is completely under the sway of Morgoth or Sauron, can it be considered liable for its actions? I would say no, the Balrog has no choice but to act according to Morgoth/Sauron's will.

Dragons though, being more independent, seem to have greater responsibility. They seem to choose to be evil in a far more obvious way than Balrogs do.

Now, this can be concluded in two contrary ways, depending on your definition of evil. Balrogs can be considered slaves to evil, and thus less evil than the Dragons who choose evil. But conversely, Dragons can be considered flawed (extremely flawed!) beings who retain the chance of doing good. Balrogs can never do this and thus are more evil.

Which one?