Don't know which amp is better, however check out this link:
http://www.rodclark.com/prologue.htm
Owner seem knowledgable, credible and most of all, previously had cav50 and replaced it with a Primaluna Prologue 2. In NO way am I saying Cayin A88T = PrimaLuna, however they are from same factory and kt88/el34 capable.