280 is pretty much a 28A with a pointy front.
Never heard of a 280F.
28F yes but thats a different beast as is the 28C/280C. All turbocharged.
280 has:
HIO360 C1B rated at 205 BHP - 28A has a C1A - same BHP
MTOW 975 KG - same as a 28A
Same narrow tail rotor blades.
No Turbo.
As long as you don't push the weight to the max on hot day they are fine. Pedal turns in the hover become interesting then. That's the main gotcha I've found. Apply a lot of tail rotor pitch and you will run out of grunt and gently descend to the ground which can be inconvenient. Allow a few lb under MTOW and it's all good. Just my experience .
I've had 2 28As.
BDKD for 15 years now.
Great helicopter.