Currently I have got a beta version of the WebPanel 1.2.5 with improved loading times at the users page
(A DB with more then 5000 Users loads now in ~260 ms on a avg host; the actual query takes ~30ms).
If you have got problems with the loading times, please post in this thread and I will send you a link to the beta.
(Its a beta because its a quick implementation (copy and paste with small changes) of something I plan to add in the upcoming 1.2.5 release)