sounds like either something you installed or added is causing the lag since nobody else has reported any
here's a snapshot of my roster if anyone cares to posit a guess:
CTMOD 2.3
System ROM 168MB (55 free)
Internal 167MB (38 free)
SD card 29GB (20 free)
SD card a2sd 2GB (1.9 free)
RAM 283MB (94 free)
A2SDGUI 0.9.9
Account and ...settings 2.3.5
Accounts
Android keyboard 2.3.5
Application Widgets
audiotuning 1.0.0
Bible 3.7.2
Bluetooth Pairings
Bluetooth PBAP 2.3.5
Bluetooth Share 2.3.5
BluetoothTest 1.0
BrcmBluetooth Services 1.0
[Bookmarks...browser 2.3.5
Calculator 2.3.5
Calendar 1.1
[Calendar] ...r Storage 1.1
Camera 17
Certificate Installer 2.3.5
[Alarms] Clock 2.0.2
com.android...nmenu 2.3.5
com.samsung.internal 2.3.4
com.samsung..oneinfo 2.3.5
com.sec.andr...nloads 2.3.5
Contacts 2.3.5
[Contacts/...Storage 2.3.5
Country, Lan...e,Time zone
DataCreate 1.0
[Voicemail] Dialer 2.3.5
[SMS/MMS/A...Storage 2.3.5
Dolphin Browser HD 7.3.0
doubleTwist 1.6.3
Download Cr...h 2008-01-31
Download Manager 2.3.5
Downloads 2.3.5
DRM Protect...Storage 2.3.5
DRMContentLauncher 1.0
Elixir 1.12.5.3
ES File Explorer 1.6.1.0
Fast Reboot 1.8
Gmail 2.3.5.2
Google Calendar Sync 2.3.7
Google Contacts Sync 2.3.7
Google Partner Setup 2.3.7
Google Service...ework 2.3.7
Google+ 2.3.0.240337
Ivona Text...h HQ 1.0.12b
JuiceDefender 3.8.8
JuiceDefende...ltimate 3.9.0
LogsProvider 1.0
Maps 6.0.3
Market 3.4.4
Market Feedb...Agent 2.3.7
Market Updater 1.0
[Playlists]...Storage 2.3.5
Memo 1.0
[SMS/MMSP...ssaging 2.3.5
Music 1.0
MusicPlayer 1.0
My Files 1.0.0
My Uploads 1.5.13
Network Location 1.0.0
Package Acce... Helper 2.3.5
Package Installer 2.3.5
Pico TTS 1.0
Quadrant Standard 1.1.7
Quick Boot 4.1
QuickPic 1.5.3
RilErrorNotifier 1.0.0
SD-Booster 1.5.2
Search Appli...rovider 2.3.5
Security Storage 2.3.5
Sense Analog Clock 3.2.3
Service mode 2.3.5
[Wallpaper/...etttings 2.3.5
[Settins/B...Storage 2.3.5
Setup Wizard 1.3
ShutdownApp 1.0
SIM Toolkit 2.3.5
Speed Test 2.0.8
Status Bar 2.3.5
System Updates 1.0.0
SystemInfo 2.3.5
TeleNav GPS...6.1.6201406
Timeriffic 1.09.12
Titanium Backup PRO 1.2.0
TTS Service 2.3.5
[USER DICT]...tionary 2.3.5
Voice Search 2.1.4
Wi-Fi Access Points
Zeam La...r 3.1.10
initially when you boot up and start using it everything seems to work ok, no FC's or error boxes, and you can flip screens and scroll menus ok, but anytime during daily use, i frequently notice that many apps and actions have major lag and sometimes even become unresponsive (hangs)
most noticeable are things like dialing numbers or starting/stopping certain applications, and any kind of multitasking or switching between apps or performing multiple actions
i guess it could be something as simple as JD screwing with the speed, but i'm pretty sure it isn't because of app conflict or too many running at a time since it lags with no apps running (except for system or background apps)
it never has become completely unusable, but the constant lag does tend to get old real fast