(imported from http://blogs.codehaus.org/people/avasseur, read comments there)
Jonas and Eugene from Terracotta - the Naturally Clustered Java provider and maker of OpenTerracotta - have published a very interesting paper on industry use of AOP and point out some limitations present in current AOP frameworks: "Clustering the Java Virtual Machine using Aspect-Oriented Programming".
"application startup time with AspectJ load-time weaving [which I partly authored] was ... slower and memory overhead was ... bigger ... when comparing with similar transformations done with either the Terracotta runtime or the AspectWerkz AOP engine [which I authored with my friend and former coworker Jonas]."
This comes to no surprise to me as AspectJ is born for build time weaving and Eclipse integration and AspectWerkz was born for load time and runtime weaving. As author of both (as we joint forces from AspectWerkz to AspectJ back mhh.. 2 years ago) I was unable to get the best of both world in one engine as we initially focussed on features integration - such as thru the @AspectJ style that is annotation-defined and driven AOP. Since that time my open source bandwith has been drawned due to work engagements. That is unfortunate as I believe there are no technical reasons for this multi-weaving-optimized engine to not happen. Fortunately AspectJ is strong on runtime performance which is something you really have to consider as well.
Their paper is available online on AOSD 2007