I have both around-ear QC15 and Etymotic hf5 and er6 IEMs. Without going into the sound quality (etymotic runs circles around Bose) the main difference is that while the Bose screens the engine noise very effectively, the Ety's will screen out
everything (35-42 db according to the manufacturer) This can be an issue if you want to communicate with the FAs, etc. I use both types, though.
For sleeping I just use the highest rated foam earplugs I can find, at ca 10 cents a pair
