I'd say either/or, but probably more towards the receiving end (albeit for different reasons than some others have stated)
What I mean by this is I'm not really interested in "sub" (or even "dom") stuff, at least not a personal level. I DO, however, like to see my favorite heroines in a submissive, defeated state, and I think it's easier - narratively speaking - to achieve that when the heroine is in the player position, rather than the AI. When an AI heroine is beaten, the match is over and the game moves on. When a *player* controlled heroine is beaten, the GAME is over, and everything comes to an end. It makes the stakes higher, and drives home the cruel finality of the heroine's defeat.
However, like DeNice said years ago on the first page, decent "receiver" ryona can be kinda hard to do, since I don't like to just sit back and let the computer win, and I'm usually pretty good at fighting games. My ideal ryona situation, gamewise, is usually a well-fought, very difficult match, whose outcome was at least somewhat close in one or more rounds, and was immensely frustrating to lose - generally, because for a few brief moments I thought (or at least hoped) my heroine might actually win. You know, one of those times where you want to throw your controller at the TV and Gamer Rage because of that cheapass cheating fucking computer rarrrrggghhh. Of course, that precise situation is very hard to achieve on purpose, either as the inflictor or as the receiver, and I often find myself throwing matches because I'm too close to winning - much to my cock's disapproval.