Videos play exactly the same (from what i can tell) on WM5 as they do on WM6.
Using TCPMP, i had to change to the Raw Buffer in order to view an AVI file normally.
Before i did that, it was horribly choppy.
Overall, i'm happy with WM5. The only thing that is upsetting me at this point is
1. Knowing that i had to use an older OS to make my phone better
. This bothers me because as a former 6700 owner, we have been waiting for WM6 since FOREVER. I get it and find that the grass is greener on the other side...lol
2. HTC Album doesn't work with WM5. Not that i use my phone to view pics all the time, but it is just so damn impressive to show pics off using the album!
OTher than that, i really can't find anything wrong with WM5 on the mogul (yet)
-s