Top Lane Pantheon: Deathfire Touch vs Thunderlord's Decree

As my most favored champion, I put the most effort on improving on the Artisan of War. With the recent Flat Armor Pen--> Lethality change, I no longer am sure whether to take Deathfire Touch for stronger poke power and overall sustained harass damage, or Thunderlord's for increased burst damage. My arguments for each are as thus:

Argument for Deathfire Touch:

1. Easier to constantly proc as opposed to Thunderlord's, resulting in constant damage on the opponent
2. Mastery distribution results in an arguably stronger late game
3. Stronger AD scaling than Thunderlord's

Argument for Thunderlords:

1. Precision still offers flat Armor Penetration component, albeit with some scaling now involved
2. Level-based scaling means increased damage in lane without having to go back to shop for a increase in damage
3. Burst based damage, which arguably cannot be as easily mitigated as DoT

Statistics on websites reveal that Thunderlord's is greatly preferred, however, I see alot of higher ranked Pantheons (ex. Platinum+) run Deathfire instead.

Also, could someone tell me which I want to run against non-tanks, and which against tanks? I hear alot of mixed results in this.

Thanks!