Are you sure that a strait 414 has a gross weight of 6765? The 402B I fly, which is basically an unpressurized 414 only has a Max Gross of 6300lbs. The 402C (unpressurized 414A) has a Max gross of 6850lbs. I really like the 402, the C is obviously far superior to the B, but the B is still a very nice plane. It has decent performance as long as both engines are running, but single engine performance is very poor. They also don't do too bad in the ice, I fly em up here in the great lakes year round and have yet to have a day ice would stop me from going up.
The C model really does have ALOT better performance, that extra 8 feet of wing REALLY makes a big difference. You get an extra 550lbs gross weight which is basically all translated into useful load since the C doesn't weight much more than the B, and it flies much better at gross than the B. It's also about 10kts faster and carries an extra 43 gallons of gas standard. If you can afford the 414A your really making a step up in capability.