i have an older x-arcade and I have not had any issues like this with mine. I did have a problem with the cheap usb adaptor they sold me to use with it, but when connected to ps2, it is fine.
mine didnt get stuck, but if i held a button or direction for a few seconds, it would stop working until i released it and pressed it again. but like i said, that was only with their crappy usb adaptor.
i have had mixed reactions to x-arcade tech support. i've contacted them for two different concerns. one time they helped me out right away, the next time i never even got a reply.