i give PSN and XMB an edge.. Microsoft messed it up with the last price hike for XBL and the last dashboard redesign, those white panels are blinding, make my eyes bleed, Microsoft should've gave us the choice to customize/change color, oh! and back to 2D display ..the dashboard Blades were nice and so were the floating 3d panels from the second version.
XMB has the option to give you animated/dynamic backgrounds, also the XMB is smoother to navigate and the colors are soft and gental to your eyes .
Overall Presentation goes to XMB/PSN .
Performance: PSN/XMB = XBL/dashboard
XBL/dashboard Pros: is a little more straight forward/simpler.
About the cross chat, when sombody joins my party chat and start talking ramdomly other than the game we're playing it gets annoying and there I tell them to join the game when he's ready to play with us ..
So, I dont think that feature "Cross Chat" is worth to pay for.
It's only matter of time when PSN gets the "Cross Chat" feature and it will be at no cost too. (I could careless about that feature)
I like both (XBL and PSN) but like I said I gave it an edge to PSN/XMB.