But,
I'm familiar with NTTC, but I'd never heard Iris D's cover. I agree that it's the best take on that (very moving) song that I've ever heard. As you noted, it captures a certain essential melancholia of life. It's a very successful commentary on a widely shared experience IMO and an excellent example of insightful writing, as well as a beautiful interpretation by Iris.
Fantastic Place is an entirely different kettle of fish. It is a celebration at a time of sadness, which is why I find it such a singular work of art. It may be more or less moving (to any given listener) than NTTC, but I was really commenting at the audacious nature of the undertaking, as much as anything else. It's not a sad song, or a mournful one, it's actually joyful - with the pain of loss lurking unspoken beneath the lyric.
Segueing neatly to Frogman's comment. I agree that The Beatles were underwhelming instrumentalists. Not bad - but not particularly compelling, either. I used to frequently argue this subject with my guitar teacher. He felt that the guitar playing in The Beatles catalog was remarkable. I believed that the ideas and arrangements were notable, but the playing (particularly the solos) rarely impressed me. There were exceptions (Something, for one), but I rarely go back to The Beatles for their playing.
Interestingly, "Fantastic Place" includes a wonderful, short guitar solo from Tillbrook that really serves the song. This certainly isn't Hendrix, Clapton, Van Halen guitar playing - it's more in the spirit of Chuck Berry (or Dave Davies, Terry Kath, Todd Rundgren, Lindsey Buckingham, etc.), a short and eloquent variation on the melody that intensifies the momentum of the song. In this particular case, it ends with a stuttering walk up the neck of the guitar and sort of spills into a gospel flavored "middle eight". The gospel touch is just a perfect complement to the spirituality of the lyric at that moment:
(Sung to the dead)
"When I'm near you, I can see you,
When I'm near you, I can hear you,
When I'm near you, I can feel you"
IMO, this is a tremendous bit of song craft - and one more reason that I hold this song in such high regard.