Do you understand why LW increases your effective lifesteal? I'll explain if you're confused, but basically LW gives you more life back while also dealing more damage to higher armor targets.

Lifesteal is based on the damage you do. Thornmail reflects damage based on the damage before mitigation. So it's very possible that, with high enough DPS, you can have three BT's and still be taking damage from Thornmail because of how much armor he has. If you do 1000 damage but it's reduced to 100, Thornmail will reflect 30% of 1000 (which is 300) but you'll only leech back ~25 life (with 25% lifesteal). However, with LW, you're making them mitigate less damage, so even though they will reflect 300 damage in this scenario, you'll be dealing more damage per strike meaning you'll be getting more leech.

Awesome, thanks for all the info

id like to point out what i meant by my previous comment, its true that champions like vayne, corki, kog benefit more from double PDs vs LW in terms of damage in a straight up duel( no movement, shot for shot trade) but like Ken said because of orb walking your attack speed goes down and it no longer becomes worth it.

Also keep in mind the times when an adc isnt in a safe position to have a consistent attack, like for ex: if a malph is zoning you with the threat of ult while you have not protection from your team. In those situations you are forced to sometimes safely poke and back off to a safe distance until it is safe to charge forwards, in these situations your auto pokes will be much stronger as well as you abilities like ez Q when you have LW.

The only champion that i ever considered trying double PD on was Vayne because i feel she has the ability to get off more auto attacks in a fight then most adcs when played properly but i quickly realised that it was the wrong choice the second i got hit with malphite W and had no choice but to die slowly XD, it might work tho if your completely safe at all times and can auto attack freely. Other then situationally(one situation) on vayne no other adc would really have a chance without LW, its just that some receive less benefit from it then others.

So that being said, on what heros would u guys go 2x PD or 1PD 1 LW?
Check out this thread, on Last Whisper being overrated on certain champs
http://www.reignofgaming.net/blogs/a...t-last-whisper

Graves
2x PD
Gains quicker stacks of his passive
Refreshes E quicker in combat
More auto attack DPS, less skill shot damage
1PD 1 LW
Skill shots do more damage
Kills bruisers with 150+ Armor quicker
If you have to kite, you will not maximize the high attack speed of PD's

Vayne
2x PD
Procs true damage more frequent
Procs the bonus damage from ult more often
1PD 1 LW
2/3 auto attacks would do more to high armor targets

Corki
2x PD
Procs more true damage passive
More dps from auto attacks, less from skill shots, skill shots have low AD ratio
1PD 1 LW
His skill shots reduce armor, making LW less effective
His passive does true damage also making LW less effective

Ashe
2x PD
More MS to kite, although the slow is prob enough to kite
Prob wont maximize the attack speed during kiting
1PD 1 LW
Has no anti tank, bruiser mech, so prob needed
Would maximize damage during kiting
Only has 1 skill shot with low damage though

Ezreal
2x PD
Doesnt need the mobility of 2 PD's
The crit chance is nice, but LW is prob better
1PD 1 LW
His only anti tank mech
His Q will hit a lot harder

so thoughts on all of that?
post who you would go 2x PD on and who you get LW on

Thx

I prefer LW.

your math is based on a perfect world type of scenario.. In that case BC might be a better item than LW as well if you get enough auto attacks in.