Thanks for the info - could you expand on the COMET techniques - lots of info on the web but it's all over the place...

I've got a table that stores when each REPORT is started and when it completes - I'll be able to use that at each customer site to fine tune the experience as we learn from usage.

If most reports complete under a minute then a simple AJAX post - with a little spinner animation - waiting for the status to go to COMPLETE - should be ok - right?

I'll have to see how many "long" running reports we have. Some reports embed JPG logo's onto the page - and PDF drivers can take a bit of time to absorb that kind of output.

I've seen report cards at my bigger high schools take 4 minutes to complete - that's a long time.

If I see the initial request reaches the 60 second moment - for instance - and decide to return a status of "STILL RUNNING" - could I then do AJAX POST's for status changes every 15 seconds, for instance. That would mean about 16 requests for a 4 minute report to determine that it finished.

Is 16 POST's over 4 minutes eating up too much bandwidth in your opinion?

It would only happen for a report that exceeded the initial 60 second POST...