I'm a loyal subscriber to Wincustomize, I love this program, but this problem of the pages loading so slow is so frustrating, and exasperating, I've had thoughts of discontinuing my account, maybe just using Style XP to alter my desktop.
1. WinCustomize is not a program
2. Style XP will not improve on how fast the WinCustomize site pages load.
3. As Philly has mentioned, Stardock are working on the code for the WinCustomize web site and hopefully you will see improvements in the near future. His suggestion of clearing the browser cookies can help in some cases.