I’ve been having issues with intelliscreen off and on since 3G.  I decided to give it another try after one of the updates mentioned improvements in performance (hopefully better memory garbage management).  Well v2.26 seems to be working pretty well.  At least for the last 5 days. 

If you run anything before 2.23, you may want to have another look at intelliscreen.

Version 2.23 Bug Fixes:
Fixed: Large memory/performance enhancement
Fixed: Home key non-response issue after crash
Fixed: QuickGold shows on lock screen
Fixed: iPod minimized after unlock when was showing before lock
Fixed: Sluggishness after iPhone is on for a long time 

Version 2.24 Bug Fixes:
Launching app from Lock Screen with PassCode freezes SpringBoard
QuickView background distorted
Expired License causes SpringBoard overlay
Mail App changes account even when not IS Mail Launch 
Preview/Layout Screen Height
QuickView Mail Memory Fix
IntelliScreen may show on SpringBoard on reboot

Version 2.26 Bug Fixes:
Sometimes IS shows when in Call
Dutch showing up on Danish Locale
Weather Labels not aligning with City when creating new Weather cities
Sometimes can not slide to unlock with QuickView Screen 
Calendar Alerts show alarm time instead of event time
Mail may not always show all messages
IntelliAlerts may alarm during outbound calls
IntelliScreen Settings App doesn’t always close properly via Apply button
Calendar Meeting Invitations cause homekey to not respond
Calendar Meeting Alerts have wrong day of week
Multiple Calendar Meeting alerts at once shows only blank with wrong date