Freelancer
More Cargo (20t vs 10t)
larger power plant (5 vs 4)
Larger Main Engine (2 tr5 vs 1 tr4
More Class 2 weapons (4 vs 1)
more class 5 weapons (1 vs 0)

Cutlass
More upgrade slots (12 vs 10)
more meanuvering thrusters (16 tr2 vs 8 tr2)
more clas 1 weapons (2 vs 0)
more class 4 weapons (2 vs 0)
Comes with docking collar
comes with tractor beam

So the freelancer is faster, has more cargo and more weapons. The cutlass is more meanuverable and more versatile (upgrade slots) plus it comes with a docking collar and tractor beam.

If you go here you can view them side by side and compare them.

https://robertsspaceindustries.com/ship-specs

Also, you might consider the avenger as it is the same size as cutlass but cheaper.