Aye, I don't even touch combustion engines, with magmatic engines sitting right there on the NEI list, begging to be used. To even be effective, you've got to give the combustion engines a refinery to make fuel, which requires a fair bit of power, got to hunt oil, which can be a pain in the ass, not to mention finding a way to pump all that oil back to your refinery...not sure if they've fixed the teleport pipes disappearing when chunks are unloaded or not.
But, all in all, yes, magmatics are much easier to use, and if they get too hot, they just shut down. Less MJ/t, but they're more easily mass-produced and with a nifty little hell pump setup, can be fed with effectively limitless lava, giving you limitless BC power...always a nice thing to have, lol.