Almost...
By Dan Murphy on March 7, 2009

I came from a pair of Ultimate Ears Super.fi 5.EB's. I had lost one of the ear buds on the ski slopes and was simply going to repurchase. I read the reviews on these Shures and took a risk.
The vote is still out.
The highs and mids are much better - without a doubt, however the low end is just not what I had been used to. Perhaps I am just one of those "animals" who can't appreciate true bass.
The fit and comfort is much better although I have yet to find the perfect groove for my ears.
I'm certainly not disappointed but suspect I might need to upgrade to the 530's to help fatten out my low end needs.
Shure SE420, good choice
By archigius on June 10, 2008

If the editors' definition of tight bass is balanced, equilibrated, they are right; if they mean weak, they aren't.
These are one of the most equilibrated IEMs i've listened, meaning the bass is present, clear but never overhanging the other frequencies.
So i can hear a good and strong bass where it is strong, and a less prominent bass where the song has it so.
Mids on Shure IEM are a leged, and on the 420 too, very clear and detailed.
The 420 has great hights too, well balanced with no sibilance, but no so emphasized.
I've them by three months, listening a lot of musical genres, and they've never distorted a single note.
Fantastic soundstage, is incredible on acoustic guitars!
The SE420 responds very well to equalizer when it is needed; i use the equalizer on albums with bad studio recording quality.
In other words, these are hight fidelity IEMs, with a lot of details across the entire frequency range:
the only thing that can give poor results is a bad sound source or poorly encoded mp3 files.
Comfort and fit also are excellent, the best for comfort, sound quality and isolation is to use the PA910 black foam sleeves.