What is the current meta PVP ship? Is the FDL still leader or new Krait changed something? (Planning to use PAs)
AFAIK FDL is still king. Slightly better shields (which are less vulnerable to Feedback), higher speed (non-boost, basically the same on boost though), but its unrivaled manoeuvrability is still what sets it apart. Krait has better firepower due to the SLF, but the FDL's zoom and boom is still dominant.
1v1's will mostly come down to skill; if the FDL can snipe the SLF, the Krait's in for a rough time as the FDL flys circles around it. If not, the FDL will struggle against the superior firepower of the Krait. If you prefer flying the Krait, I'd say that's the more important factor.
For wing fights however, the SFL will be gone in seconds, the Krait's reliance on SCBs will be punished by feedback spam and the lack of maneuverability/chaff slots will make the FDL the superior choice by a larger margin. Plus, the FDL doesn't cost you a crew member when you lose.
Both are viable, just like most ships, but the FDL is still 'meta'. Personally, I see the Krait as a poor man's 'Vette; I see little point using it in PvP when you can just save up/rank grind for the Vette, which will outperform it in almost every respect (by a large margin). FDL is there because maneuverability is king, and no amount of firepower will ever change that.