I saw Patti in the original London production back in the day. Christ, her voice was phenomenal back then. I have since seen her in Gypsy (twice) and recently in War Paint. I have also seen her in two different London concerts. Her voice is still in good shape, but the sheer vocal power in Sunset (not really given its justice in any clip I've seen) was stunning and unlike anything I've ever heard. In the final reprise of With One Look at the very end of the show (which they eventually worked in to the LuPone version) she did this amazing vocal riff on the 'Meeeeee' - it was like she climbed somehow on the note. Can't describe it musically, but it was amazing and the most vocally-powerful and intense thing I've heard. This was towards the end of her run in the production. The final performance clip on YT is actually disappointing in comparison- she cuts the note short. On the day I went, however, she sustained the note both times and did this riff described above. A certain Seth Rudetsky would have loved that performance.