I would say it doesn't really matter. One is not necessarily better than the other. Reusing an existing rim is fine. I've heard of many people that have done exactly that.

If price is an issue and you're up to it you could just get the SA hub and some new spokes and rebuild the wheel yourself with the same rim for about $30 and the price of the hub. If you have a reasonable shop you could have them do the same thing. My local shop would do it for $40 labor and $1 per spoke, so about $76 plus the price of the hub. Or you could buy a prebuilt wheel for $120.