FDL. Having said that, in my experience of flying a Python, it often comes out on top in a 1v1 versus an FDL, simply because it is much more tanky, and the FDL pilot has to do some very good piloting to punish the Python's worse maneuverability.
In wing fights, however, especially anything larger than a 2v2, the Python's sluggishness means it is very easy to focus down, whereas an FDL pilot can hope to evade focus fire.
For reference, the Python I fly has bi-weave shields, 5D+4D MRP, the rest heavy duty HRPs. With 2.4 engineering, that comes down to 4200 hull (could be nudging 5000 with 3.0 rolls), and about 550MJ of shields.
In wing fights, however, especially anything larger than a 2v2, the Python's sluggishness means it is very easy to focus down, whereas an FDL pilot can hope to evade focus fire.
For reference, the Python I fly has bi-weave shields, 5D+4D MRP, the rest heavy duty HRPs. With 2.4 engineering, that comes down to 4200 hull (could be nudging 5000 with 3.0 rolls), and about 550MJ of shields.