Can anyone comment on Shure’s sound isolating earphones?

Specifically:

• Do they really block out ambient noise in an airplane?
• Are they comfortable?
• Would you buy them again?

I have the "Clarity Aloft Pro" and couldn't be any happier with a headset. It's so light and comfortable that you actually forget that you're wearing it. Check it out at http://www.clarityaloft.com/

I have the Shure E5c's (now discontinued).

I had the Bose QuietComfort 2 before and these block out as much as those did with the ANC activated - and without the bulkiness. They may not be quite as comfortable, but I've had them on for entire transatlantic legs - not an issue. I think the Shure sound quality is noticeably better as well.

So for Q's 1 and 2 - yes (just make sure you use the right sized ear-plugs - they come with like 9 sets - 3 sizes of each variety).
Q 3 - this is my second pair (first bought a lower end set, then upgraded).

I've been very happy with them