I've spent the better part of two nights going back and forth between these two headphones. Just my personal thoughts made from the notes that I took...two cents as they say....likely worth that.

 
As a bit of a backdrop, here are my thoughts on the differences between the R1 and R2 LCD-2s:
 
http://www.head-fi.org/a/comparisons-of-lcd-2-rev-1-and-rev-2
 
 
Ergonomics/Aesthetics

Both headphones look like they’re part of the same family with some distinctions (kinda like the Baldwin brothers I guess). I prefer the darker wood colour of the LCD-2s, but the newer earpads of the LCD-3s are fantastic for improving the comfort and reducing the clamping. I also like the brown leather look of both the earpads and headband on the LCD-3s.
 
The other thing I do appreciate is the more angled headphone connectors on the LCD-3s...helps makes turning one’s head a lot easier.

Weight-wise they are about the same as far as I can tell and sensitivity wise, I find the LCD-3s a tad easier to drive than the R2s (which in turn were a bit harder to drive than the LCD-2 R1s).

Okay, now let’s move on to the most important....how do they sound?
 



Setup:

Azur 650C CD Player --> Wyred 4 Sound DAC-2 --> Woo Audio WA22 and Schiit Lyr

Tubes:
WA22 (Sylvania 7236 Power Tubes, CV181-Z Shugang  Treasures, 274B Sophia Princess Mesh Plate Rectifier Tube)

Lyr (GE 6BZ7 Driver tubes)

To keep things simple, I used the stock ADZ6 headphone cable (single ended). My balanced Silver Moon Audio V3 headphone cable was not included in this comparison. BTW, the ADZ6 is their best cable yet. Incredibly light and ergonomic.


Music:

Moving Pictures: 25th Anniversary Remaster:  Rush

Jazz at the Pawnshop Vol. 1 (Limehouse Blues, I’m Confessing)

The Black Album: Metallica
 
Long Player Late Bloomer: Ron Sexsmith


 
Sonic Character

These  two headphones have the house “Audeze” sound. I guess like how Grado headphones sound like well...Grado headphones.


Let’s start off with the bass. The LCD-3s have retained the classic Audeze bass response, deep, defined, impactful (yet controlled) and well, just the best quality bass I’ve heard yet. But there is a bit more control and definition to the bass with the newer version.  When I heard the bass on the LCD-2 R2, I didn’t think it could possibly get better, but I do find the LCD-3s improve on it still. Not huge, but noticeable  and I do appreciate it. Listening to “Enter Sandman” by Metallica, the bass details are more present and clean on the LCD-3s with a quicker response, but again, not a big improvement as the LCD-2s were pretty spectacular in that regard.

The mids are very similar IMO...very liquid and nicely placed in the sound stage. Clean and true to life...simply amazing on both headphones.

While I really liked the treble improvements of the Rev. 2 over the Rev. 1s, the LCD-3’s treble improvements are among the biggest gains that I’ve found. They are still Audeze headphones....read in here “NOT BRIGHT”, but the details on cymbals are more present with shimmer, decay and sound-stage placement that is happily welcomed by my ears. The tea cups clanking and cymbals on Jazz at the Pawnshop sounded that much more real and three dimensional on the LCD-3s. As a result, the sense of air and space has also improved. Great job Audeze.
 


Sound-staging/Imaging

The other area of more substantial improvements are in the sound staging and imaging. The LCD-3s now keep up easily with my T1s and HE-6s in this regard. Only my HD800s are better with respect to sound staging. I felt this was a  small weakness with both revisions of the LCD-2s. Thankfully the LCD-3s have kicked it up a notch (not to sound like Emeril here, but I really liked this change). A quick side note, I do find the LCD-3s slightly quicker than the LCD-2s throughout the frequency spectrum and less forgiving of poorly recorded material. The best Audeze headphone for making bad recordings sound great still go to the LCD-2 R1s.

Conclusions

Both are outstanding headphones and two of my personal favourites. Both are voiced with the same Audeze DNA and both offer a true to life sonic experience like no other headphone I’ve heard. With that said, I do prefer the more evolved sound of the LCD-3s. Again, the differences here are not massive, but enough for me to keep my LCD-3s (and sell off my LCD-2s).
 
I found the sound signature, bass quality and true to life tone of the LCD-2s was very revolutionary in the headphone industry, and the LCD-3s continue to evolve that sound. The LCD-3s are not as revolutionary in that regard; likely because that’s just how good the LCD-2s are.
 
Now let’s address the big pink elephant in the room...the price. I am a bit saddened to see headphone prices skyrocket like speaker rigs over the past few years...and $2000 is a bit much IMO. I would have preferred them priced at $1500-1600 range.  That said, the LCD-3s are my new favourite headphones in my collection.
 
Update:
 
So after some reports of LCD-3 owners sending back their "unveiled" LCD-3s to Audeze and for a check up and having the returned ones sounding even better, I got really curious. I contacted Sankar and he offered that I return them too. The thicker foam in front of the drivers has been replaced with a thin fabric that is quite a bit more transparent than the original foam. Purrin took his unveiled LCD-3s apart to find that the damping behind the drivers was changed too.
 
So how do they sound? They aren't totally different from the non-veiled pair that I sent in last week, but the mids are a bit more forward and the treble seems less pushed back (but still smooth, not peaky like the LCD-2 r.2s...only in comparative terms...the LCD-2 r.2's treble is still outstanding and better than most cans). My returned FR graph looks like the ones posted on the LCD-3 thread now. My original looked almost identical to the one Skylab posted on his review. Overall I'm even happier now.
 
The improvements in the LCD-3s now make the 2x price tag much easier to take IMO.
 
My first FR graph with my headphones when I received them in Nov. 2011:

 
And now my new FR graph from Audeze (I've gotta say all of the recently released LCD-3 graphs all look very similar):