I've just switched from Penultimate to UPad. It's very similar in how the writing feels, but has way more features. I've had difficulty working with PDFs where the writing would be very choppy, and UPad is the first one I've used that writes smooth over PDFs. Also, I like the wrist protection on UPad over Penultimate, not to mention working in landscape and nice zooming.
Im a biology student and we take insane amounts of notes so I think people would be happy with this one. It needs audio recording built in so I can stop using audiomemos.