Well, based on all the reading I've done (and, believe me I've done plenty) I'd say you have absolutely nailed the general consensus. I have waffled back and forth between the X and the 3 (currently own LCD 2, rev. 2) and I finally settled on the X which will be here tomorrow. I finally decided against the 3 but it was REALLY close. I believe the 3's are possibly due for an "update" so I'm hedging my bets. Now, I really do like my 2's quite a bit so I'm anxious to do the head to head comparison to draw my own conclusions. My main set up is the Mjolnir/Gungnir stack and the Mjolnir allows two headphones to be connected at the same time so that will facilitate switching back and forth while listening to the same music. Obviously I'm anxious to see how the real life comparison goes!
The Mjolnir/gungnir stack really brought my LCD 2's to a new level so I'm guessing the other LCD headphones will play well with this combination. You know how it goes in this hobby; the lure of something "better" is hard to resist though at this level personal preference plays a huge role. I saw the LCD 3 as an improved version of the 2 and the X as representing a slightly different direction in terms of bigger soundstage and more detail. Of course I won't know until I listen so I'm anxious to see how they compare!