I just listened to "The Paradise Syndrome" CDs back to back. First the LLL and then the Royal Philharmonic.
In the LLL, I think I'm hearing a harpsichord during Spock's climactic mind meld, although it isn't listed in the orchestra credits.
The original is of course unbeatable. "Miramanee" is better at the original tempo, as many have observed; it gets her lively youth across. "Forest Montage" is the most important cue that the Royal Phil omitted. And "Miramanee's Death" plays out more effectively in the original. I got into it and actually welled up a little. It's great.
That said, I still got tremendous enjoyment out the Royal Phil. It's a tight, highlights-only presentation, so the 20 minutes go by fast. In a sense, it's like when you skip the previously unreleased atonal cues in THE WRATH OF KHAN. And I'm not tired of this music as the LLL comes to a close, so the re-recording is like an encore.