Right now they're both alpha, so they've got not a lot of customizations. Also the CM is only for D802 right now, so if you don't have that, its not even an option. As far as I can tell, the houstonn's PA is basically CM so far as a lot of the features that PA is known for such as PIE, Holo, hybrid setting etc are not present. However, I'm sure once these roms get out of alpha and beta, there will be more differences.
Siemens S40 > HTC S710> Sony Ericsson P1i > Samsung S8300 UltraTOUCH > HTC Magic Black > HTC Desire > Nokia N8 > Samsung Nexus S > LG P999 G2x