i have western rivers seems to work pretty good. you don't have to buy a card to expand your sound. all you need is the usb cord which is supplied with the unit. western rivers has a site to get i think around a 150 differant sounds. you can save them in a file and use them anytime. just a click and drag. i have also recorded all my tapes onto my computer and changed them over to mp3's and you can use any of them. the unit has space for 30 minutes of play time so you don't have to use short sound loops. which i think is better. the only bad thing that i can see is that you have to step down threw your sounds. this why i only keep 3 or 4 sounds on my unit at once. also the remote works out to about 200 yards.