Tomcat 6 was not fully tested for Presto 2.7, so there is no way to definitively answer your question. I know there have been other inquiries about this -- just not sure if other MDC users have gone forward and could provide better information.
No problems. I'm just evaluating Presto right now. I upgraded our last Tomcat server to 6 last year and was not wanting to bring up a 5.5 server again.
Is Tomcat 6 known not to work? Is there a date on when it will be supported?