LIB - built on a demo recorded on Jan 26 there's a nice ascending string 'solo' brass, female choir ahhing and oohing. Harrison plays acoustic and Lennon plays some awful bass and McCartney's vocal are a little out of tune in places. This may have been covered by vocal double tracking but we'll never know. Spector wiped one of McCartney's vocal tracks to have room for orchestral overdubs.
A3 - The same take as LIB minus all the overdubs. We find that the strings solo was covering a short spoken interlude and we can clearly hear how out of tune some of the vocals are (eg 1:20 - 24 and 1:34). There's a little piano reprise that fades out.
LIBN - A different take recorded on 31 January 69, with Harrison on electric guitar and Billy Preston on electric piano. There are no orchestral or choir overdubs. The line "anyway you'll never know the many ways I've tried," is "anyway you've always known the many ways I've tried" on this version. The solo is now a tasteful organ like one from Preston. There is more straight playing on the hi hat rather than swing on the ride cymbal and a lot less drums overall. The sound is generally much bigger and less compressed.
We have to bear in mind the the LIB track was built on a demo that was never intended for release (as far as McCartney was concerned). The vocals are some of McCartney's worst and Spector did a good job of covering them. He replaced the terrible spoken section with a beautiful string section. Anthology reveals how bad the original track was. Everyone's performance on the LIBN version is far superior, so much so that it's hard to understand why Spector did not use this track. I suspect that in the remixing that every modern digital fix available was used to make this track sound as good as it does.
Verdict: LIBN by a million miles.
LIB - Let It Be
LIBN - Let It Be Naked
A3 - Anthology 3