For what it's worth, I did the Avon and Ribtec comparison at a slightly larger size a couple of years ago.
Whilst the Avon was well laid out and seemed to have some extra toys, I felt that the Ribtec hull was superior and gave me a more surefooted, confident feel.
I bought the Ribtec and have had a couple of brilliant seasons with her. She will be for sale this autumn as I'm commissioning a 7.4 m Ribtec, so if it's of interest after you've priced up a new boat at Souithampton, email me at firstname.lastname@example.org
The boats I compared were '99 specs, so materials and layouts may well have changed. Try 'em all, listen to other opinions and then go with your own gut feel.
All the Best,