A few more observations. The 360 is more likely to crash the media server. The CPU utilization will skyrocket to 80 - 90% when there is an error. I am streaming Final Fantasy 7, Advent Children and there is no CPU utilization. Older codec versions do not work so well. The 360 seems to want to try to play these where the PS3 will outright tell you that it won’t. Newer Xvid codec movies WILL play on the PS3. I would venture to guess anything prior to 2004 is going to give you difficulty if it’s not Divx.
I would also venture to guess that MCE (Media Center Extensions) will work better with the 360 since that is what it is designed for so if you only have a 360, setup a Vista Ultimate computer or a Windows XP Media Center Edition 2005. I will update this as I get more familiar with it.