Turtle Beach Catalina 7.1 Digital PCI Sound Card doesnt have hardware sound processing like all other Envy based soundcards. and "only" supports EAX up to 2.0 and A3D which is more or less a dead thing.
what the best soundcard is depends on what you use it for.
if your main thing is music and DVD playback then nothing beats a good Envy24HT based soundcard (personally i like the M-Audio revolution 7.1 because of the drivers and controlpanel)
if you're a gamer you pretty much "stuck" with a creative card. you'll find EAX >2.0 / advanced HD features only on creative cards. and the mid/high range creative cards are fully harware accelerated.
only con of creative is the software that comes with the hardware. still amazes me how they manage to get 650+Mb of software on your HD when you do a standard installation. doing a customized installation is a must.