Well, we are currently using tiles (a lot) and at the moment we are feeling that tiles performance is fact poor and we are not happy with it. We want to move away from tiles but we don't know well where to go yet (I think we will end droping struts at the end too).
Take a look at Stripes (http://stripes.mc4j.org/confluence/display/stripes/Home
), they have what seems to be a really nice "tiles like" tag library (But better IMO). I have to take a deep look at it to see if we can use it in our current developments.