Finally, I decided to do the upgrade. It was not as smooth as it looks, especially that I turned on 64 bit as default. Normally, SL runs in 32 bit mode, you need to hold 6 and 4 keys during the boot process to get into 64 bit mode. But you can also change the config to run it as default, instruction is here.
Most of the applications still runs fine, here is a few exceptions that I encountered and luckily all of them have solutions so far. Here is a list of compatibility check for SL, note that it is not the default 64 bit mode.
1. menumeter: This is a small monitoring tool that I use every day, to check network, CPU, memory usage. Good thing is it displays info on the menu bar. Old installation not working anymore, just get the latest and reinstall.
2. delicioussafari: This is a plugin for Safari that saves and opens your delicious online bookmarks. To fix the issue, just get the latest and reinstall. The new version even has a new BMW-like button
3. macfuse: This is a handy tool to help mount various file systems. Here is the fix for 32 bit SL mode, however it did not work for 64 bit mode. You can use this pre-compiled dmg for 64 bit mode. It runs great for me. You can also roll your own following the instructions here.
4. TextMate: It has lots of issues with SL, especially due to the upgrade of Ruby. First, try to get the latest release possible. But still, I am having issues with ⌘R. Textmate blog has some workarounds and I have not tried them yet, hopefully they will fix the problems in the next release.
5. MacPorts: This is another thing that caused many headache until I found this nice blog that suggests a fresh install. It worked all fine. However, occasionally, some ports will still report error of unmatched architecture. This blog also covers "Upgrading to Snow Leopard Part 1 to 7", talking about python, mysql and other upgrade tips, very handy! He also talks about building 32 bit packages using arch and lipo.
6. VMWare Fusion: The old 2.x version even won’t start in 64 bit and asks you to restart SL in 32 bit. So, you need to get the latest Fusion 3.0. The upgrade is not free.
After a week of being little white mouse running 64 bit SL. I’d say maybe running 64 bit does cause more issues than benefits. But we can debate over it. Here is a good intro if you are interested.
The best part for me is that I got back 12G free space, very interesting. It seems to be a combination of using 1000 for 1024 in calculation and cut the new OS installation size.