anyone ever stay there or know anything about it. I have a chance to trade in on RCI and I know its kind of out of the way.

The concept of "Guana Bay" and "resort" seems somewhat of a nonsequitor to me. As of when we stayed there, most of the units there are owned by full time residents. There are basically no amenities, other than the pool. The units are all individually owned. Some are in very nice shape. Some, not so much. No way I would trade in there in a million years. You have no idea what you are going to get.

isn't the surf very rough there too?

It's usually pretty rough, yes. Often people use boogie boards, etc., there. No amenities on that beach, although presumably most rental units at Guana Bay provide chairs/umbrellas/coolers for their tenants. And, as the op said, it is somewhat out of the way, for the main tourist areas of SXM. I personally didn't care for the weird, kind of futuristic look of the whole place, so not sure I would stay there again. But if I did, it would be to rent an individual unit, based on pictures and reviews of that individual unit. Guana Bay is a very residential, quiet area, which some people would like. For me, I didn't care for it.