Personally, I'd feel more comfortable with Romo.
Rivers losing V-Jax is certainly going to impact his production. Gates' injury woes and his advancing age is also a concern. There are tons of questions regarding what the hell happened to him last year. His 25 turnovers was unsettling and now that he's missing another major weapon in Jackson, I really question if he'll be in the top half of all fantasy quarterbacks. Floyd and Meachem could be a nice combo, but I'm still not sold since neither has ever shown a consistently strong track record.
Romo, on the other hand, always puts up solid numbers when he's healthy. He's had at least 25 TDs in four of the past five years and the only anomaly was two years ago when he got hurt. He has good weapons around him in Bryant, Austin and Witten. I think he's going to put up good, not great, numbers for a fantasy quarterback. He won't carry your team too often, but he certainly won't sink you like Rivers did last year.