As the boats get longer, you do get much more space, but all of your costs go up as well. Maintenance, dock/marina/mooring fees, haul outs, cost of equipment, all go up as the size of the boat goes up.
Larger boats are often far more dependent on hydraulic/electrical power. They are also harder to handle short-handed. The draft on most larger boats is often greater than that of smaller boats, which can limit where you can go as well.
On the pro side for larger boats... they're a bit safer... and have much more living area.