personally, i havent tried her ap, doesnt seem that attractive tbh, reckoning stacks the same with ap or ad and her passive and E benefit more with atk speed than pure ap... also the splash dmg on her E is based on the dmg u deal, so building ad also scales it, u would have to do the math to compare ad vs ap scaling (im lazy lol)... her ult doesnt scale with anything but u can get more out of it if ure ad or on hit due to invincible sustained dmg... if u build her ad she is amazing, with a little CDR u can keep ur E basically all the time and having a slow, a heal+speed buff, a dmg amplifier and that godly ult on an ad carry is not a bad kit... if u time your ult correctly, u can literally destroy any other champ 1v1.... on hit is really fun, ive always liked atk speed builds, kayle has 2 innate on hit procs so building on hit is viable but on hit builds tend to fall off lategame, u dont dish out enough dmg for ur squishyness.... the main drawback i see with building her ap is that ur dmg amplifier is also ur only nuke... ap will have better heals and a little more dmg out front but nothing to follow it up properly....
thats my opinion anyways, hope u found it useful

The difference basically hinges on the fact that one focuses on auto attacks, while the other tends to poke more, do a Q->E hit hit hit combo type deal.

I personally prefer Hybrid because it means her Q does relevant damage, and her heal is...ok, I guess. But it also makes her E do massive amounts of damage. If your auto attacks do about 150 damage of both magic and physical and shred resistances, what the hell can people do to stop that?

as ap kayle, i have been rushing AS on her before deathcap to make use of her E, am i going the wrong direction with this? if so can somone put me on the right path please

don't people just buy infinity edge and dancers

I think hybrid ad and ap with some attack speed mixed in looks nice.

AP Kayle gets a Lich Bane.