Just right!
The PDF Max 4 (free version) is exactly what I was looking for stress free, paper free reading for my studies. A larger number of highlighting options is offered and the app is very intuitive. I love it! The premium version offers better reading, though I dont think thats really necessary. Offers syncing via iCloud, which I always prefer.
Drosophila_Girl about
PDF Max, v4.4.0