I prefer more fuel capacity, mostly because I like to keep some reserve. If the tanks only holde 2.5 hours of fuel, that means you can only fly 2 hours max, and that's stretching it under many conditions. Nick's point about cruise speed is valid - 2 hours at 100 kts means a lot less range than 2 hours at 150 kts. That's why current Bell models are so limited - they don't carry much fuel, they are slow, and PT6s suck the fuel at a horrendous rate, so the range is pitiful. The BO105 is another model with range problems. The current 206 models, with ever larger engines, don't do well, either. If you're doing many short trips, then the speed becomes much less important.