I recently had Dynoplex's eFile installed on my 7520 and it didn't seem to have any negative effects until I tried to use the "Save to eOffice function" and then tried to view the file. For three days after that my battery life was cut in half. Finally I uninstalled eFile and the problem went away.
Current: AT&T 8300 w/Plantronics Discovery 640
Previous: Nextel BB7520 w/ Plantronics Discovery 640