So I bought Ezreal yesterday and I'm finding him fun, but I'm curious as to which playstyle is stronger. AP or AD?

Use attack damage if you like spamming the q spell, and use ability power if you want to power up the other spells. Overall, I'd say AD Ezreal is stronger due to mystic shot's low cooldown, and the extra attack damage goes great with your passive and auto attack.

I've always played Ez as AP but with CD reduction being a priority too. The faster you can get all your spells off the better and getting a lich bane makes your Q just as strong as your other spells with the nice short cd on it.

Try both, figure out which one you like better...?

AP ez has higher burst damage and a stronger ult, but AD functions better in terms of overall damage output. Going AD will sacrifice the damage capability of his W and E, but they still have their uses (atk speed de/buff, flash).