Others say...

"Double Flange Mod"
Out of the box this is an overkill for my ear canal.
What works best for me in terms, of sound isolation, sound quality, and comfort
is to shorten the length of this sleeve at the bottom as well as convert this into a
Double Flange Sleeve.
This is what I do:
The first step is cut and eliminate the top flange
flush at the top of the second flange with a sharp knife.
The second step is to flip the bottom flangue inside out to shorten
the shaft below the bottom flange with a sharp knife so the entire shaft
of the sleeve is about the length of the earbud's shaft.
For those unhappy with the price of the PA755
I haven't tried this but there is a 3 pair tripple flangue by shure: product EA306
which seems to be very similar to the PA755 and less than the price of one
pair of PA755
There is another Mod I will try later, I will leave all three flanges intact
but I will cut the entire shaft below the bottom flange flush with the bottom flange

"Not bad, but slightly overpriced"
I'm using these triple-flange sleeves with the e2c's, even though officially they are not compatible (according to Shure). They fit tightly onto the nozzles of the e2c's buds, but they do fit if you carefully slip them on, and make sure they don't tear.

Quality-wise, these sleeves work well, and are definitely easier to put in and are more comfortable than the foam sleeves or rubber tips, though I feel that the foams give better isolation. The foams are reusable only to a certain extent, however (they start to deform and harden within weeks), while these triple-flanges should last as long as you keep them clean and prevent them from ripping (latex is durable enough). I've been using them for about 2 weeks now without any problems, and am definitely glad I ordered a pair. I do have one complaint, though, and that is that (like another customer mentioned) these are a bit overpriced for a single pair of small likely mass-produced latex sleeves. I'll consider it worth it, though, if they last through the year.

Cliffs: An excellent replacement for the sleeves that come with Shure canalphones, but they should be cheaper.

"FOAM > Triple-Flange but only by 5-10%"
Firt off I want to say that I love the triple-flanges in terms of sound and comfort. The Foam inserts are a little more comfortable and isolate a little better (note better as in 10% better not twice as good or anything). However I'm sick of having to replace the foams every 2 weeks or so esp. since they cost like 2-3 bucks a pair! After a week they start to get stiff and yucky and completely loose the awesome fit and isolation. Trading away 10% of the comfort and 5-10% of the isolation is totally worth the hassle and cost of replacing the foams (if Shure or someone else sold the foams for a reasonable price things would be different). The sound quality is excellent with the triple-flanges since they isolate so much better than the grey inserts that come with the e3cs. The bass especially is excellent due to the nice tight fit. TIP: I shortened these long sleeves by cutting off the tube from the end end that goes on the e3c earphone's nozzle. I cut them off uptil the botton of the last (biggest) flange. I found the bass to be improved a little when I did this probably due to the reduced distance from drivers to ear-drums and now I can wear my ear warmers again without feeling like q-tips were being driven into my ear! :) Recommend it if youre sick of the foam's cost and durability.

"Shure PA755 Triple-Flange Sleeves for Shure Sound-Isolating Earphones"
Not a bad product, but soooo overpriced for what must be a penny's worth of latex...

"Perfect -- the difference between mediocre and great headphones"
I've been using them at night, on airplanes.. These made the difference between me not really liking my headphones very much and really loving them. They block out sound better than most ear plugs and stay in my ears. Great!