I use the Toyos and am perfectly happy with them and purchase them from Demon Tweeks at a ridiculously cheap price. Have no experience of Avons but have used Yokos, pleased with them but I found they do harden fairly quickly compared to others.
1969 4/4 1995 plus 8 1996 Plus 4 4seater 2002 Aero S1 2013 M3W 2014 Plus 8