Zodiac Futuras (especially the fastroller's) are very light, very stiff and, with the biggest engine option, very quick. At normal speed and loads they are safe and stable, the relatively wide beam ensures turning them over is virtually impossible. They ride waves best by jumping over them, you need to be brave and keep the throttle on, its exciting and pretty wet. Your body will take a lot of abuse unless you have a Sport with the jockey seat.
Having said that, the closest I have ever come to a crash in any boat was in a late 90's Futura Sport with a 60hp 2 stroke and a very big prop (It was only rated to 50hp). I got into a chine walk that went badly quickly and I nearly turned the whole thing over. It was operator error and pushing the limits that caused the issue.
They are a great boat and I would even stick my neck out and say they are the best 3.8m airdeck out there (Yes I know, thats actually the Bombard 380
), but they are a fair weather, nice day craft for inshore work.
The Searider is much more capable, but it will obviously be slower and probably older. I dont think the 2 can actually be compared, they are just too different.