The differance between MFSL Ultradisc I and II?

Hello folks!

I have a copy of the The Who Quadrophenia MFSL UDCD 2-550. It is still sealed in the original long box. How can you tell that the remaster is an Ultradisc I or II. The label on the front of the box say's ULTRADISC so I assume it is just an Ultradisc I. Which copy is the one preferred by Audiophiles?

Thanks so much!
I believe the two version used their GAIN recording method.
Thanks for the responce Qdrone!

However, how can you tell from the ouside of the box if it is an Ultradisc I or II?

The CD longbox (Remember those)that I have just says Ultradisc on the front.
The I's are more rare than the II's. I prefer the I's over the II's for better sound. The difference is that of being pressed in the US (I's) verses that of being pressed in Japan (II's). The first versions were also aluminum verses that of gold..........
There is no such thing as an Ultradisc 1, there are simply the original Ultradisc reissues and the Ultradisc 2 reissues. Your reissue, from 1991, is in the original Ultradisc series. It was never issued as an Ultradisc 2. For your convenience here is the Mobile Fidelity discography, that verifies this,

To answer your other question, the British LP is the copy preferred by audiophiles that have made the comparison.
I have the first pressing Track Record/MCA vinyl Quadrophenia purchased on the day the album was released in the U.S., as well as the Mofi CD. The vinyl sounds much better than the Mofi CD, apart from the glow of nostalgia of bonging through all four sides twice in a row listening to Advent speakers in my freshman dorm in the fall of '73.

I bought a few of the early Mofi Ultradisks and could not hear a wit of difference between them and standard issue CDs. I believe the GAIN System/UD IIs were mastered on Mofi equipment upgraded with Theta technology. To my ear these are a step up from the original UDs, tho perhaps no better now than subsequent reissues by the record companies.

THe point is that the master recordings will all differ. It would be difficult to compare a UDCD-1 that has been copied from a great 30 IPS, 2 inch Master, to a 15 IPS 1/4 inch tape that used the Gain 2 system. I really like the Moody Blues Gain 2 CDs. There are certin moments where notes are hit and does take on the appearince of a sence of realism. ( who am I kidding ) I a very general broad sence, I do like the gain 2 system better.