I've been a mile offshore of Gran Manan watching fin whales in my 10'quicksilver inflatable. Those boats handle long period sea waves, but in a chop they are wet and cold. I have been in trouble off Grindstone Island in standing wave rips and again off Hopewell Cape in a stiff chop. It can get very nervy out in the big water. A short inflatable doesn't act like a regular boat. It sits down in a hole and when you power up it needs to climb out at a steep angle and then flop down into a plane. Basicly, if you don't have enough boat for the waves you are in, you can't plane on top, so you stay down in the hole and need to make it into a land 'shadow.' They preform very well in lakes. Just imagine a 10' air matteress with a 10hp motor on plane!
There is nothing any stabler, but at speed I sit on the floor or it might throw me out. A big wave will flex the boat and toss the bow passenger and gas can into your lap. I threw my buddy high enough up when he came down he broke the seat in two off Hopewell Cape. But even with the boat flooded we made shore OK.
They are a study unto themselves and the best info I see is at:
http://rib.net/forum/
Look at the Inflatable section.
take care,
jim