Most of the replies you have received are spot on, but I though maybe I could offer a bit more insight. In short the FDL and Python are both great ship, but in my opinion the Python is better in every situation with exception to price. If you are just saving up for one of these 2 ship then you may want to consider the cost of outfitting either of them to what you would consider reasonable. I will give you a few examples including my own Python and what I would consider to be the bare minimum configuration for either ship in regards to combat to the tune of about 66 million credits.
The Bare minimum:
Python- http://www.edshipyard.com/#/L=605,5TP5T ... O7kO16y16y
FDL- http://www.edshipyard.com/#/L=60O,7RK5R ... ,7T27hG7hG
- Uncheck the cargo scoops to bring either ship to 98% power usage.
Notes: Shields- 562 to 680 winner FDL, ARM- 740 to 225 winner Python, Jump Range- 13.75 to 13.84 winner FDL, Fuel Cap- 32 to 8 winner Python, and the unused utility or internal compartment slots. Though I would say that the biggest thing to possibly note is the areas in which the FDL is already maxed out in this example i.e. power plant, FSD, and power distributor. That is the FDL does not get much better than that requiring min maxing and careful consideration to limited resources, read power, to get the most out of it. On the other hand the Python in this example can be upgraded in almost every area.
My Python:http://www.edshipyard.com/#/L=605,5Dd5D ... y4_w0KU0KU
-Uncheck the cargo scoop, fuel scoop, and both auto field-maintenance units as they are off 90% of the time to see that I am in fact at 99% power usage.
Final thoughts: Using a Vulture for combat and a Type-7 to trade for as long as possible is not only a good idea but probably the smarter thing to do.