What are your thoughts on this? For example, if I purchase Rabbdon instead of Hextech I getting:
125 + 125(0.35) = 196 AP + 196 / 40 = 201 AP 196 x 1.4 = 274 Health
Whereas Hextech grants:
60 AP + 300 / 40 = 67.5 AP 300 + ( 60 x 1.4 ) = 384 Health 10% CDR
With my math, you can see the value you're getting for only 1300 more gold! So in short, is hex tech worth it?
ReySolomon2 votesit's still good on 
WitchQueen Annie2 votesI build it on 
too (but this is controversial because I play an engage/zoning style Annie instead of focusing on building raw damage)
Geshultz1 votesStatistically Rabandon's Deathcap has a higher winrate and pickrate across the board, than protobelt so Statistically speaking Rabandon's Deathcap is better overall in general.
Rabandon's Deathcap has a 51% pickrate per 1 champion and a 59.7% winrate. Protobelt has a 29% pickrate per 1 champion and a 53.4% winrate. To answer your question, statistically no it is not worth purchasing over Rabadon's Deathcap.
PrinceOfStorms1 votesDepends on the champion.
Vlad gets both (Protobelt typically as first item because he loves all the stats on it). Ekko gets it because it helps his engage (and gives him some tankiness), since the first part of his E is kinda short. Cho gets it because it helps him gapclose. Fizz gets it for similar reasons as Ekko.
Outside of those champions it's pretty bad though.
You appear to be talking about Vlad, but your calculations are really strange.
125 + 125(0.35) = 196 AP + 196 / 40 = 201 AP
Where is your (196/40) term coming from? I know that's the ratio of Health -> AP, but he's not getting health from Deathcap, and his passive doesn't stack with itself.
As for Vlad specifically, I build it on him as a third item- getting Protobelt first because it helps Vlad deal with his god awful mobility, and Liandry's second because it lets him shred tanks in longer fights.
