Early this year we successfully built and delivered complex Aware IM solution and it was used by 1000 users heavily and at one point 200+ users at one go used it within 5 minutes and there was no problem at all(aware Im and tomcat handled everything so well and we had tons of looped complex processes thisuser thatuser...). So I know now the power of Aware IM after taking on 1000 users in production system. The only thing I wish it has SEO features built in that makes it great for google search and then google searches Aware IM internet facing apps via SEO and search rankings/URL's(SEO on google mainly works on URL's and tags inside URL's for example if users hits url's that contains /Jobs/Australia/Brisbane then next time anyone in Brisbane searches for jobs this guy comes up in google search).
Also if there are some more HTML5 cool mobile app ready samples built it will be good to start with.(I know there is one mobile sample)