Yeah, I was very impressed! Before I started using the blotting sheets I'd put powder on my nose at 7am, 10am, 1pm and 4 pm before taking it off when I got home (those were the times I wasn't in class) - the blotting sheets saved me a lot of time and also made my skin a lot healthier since mine don't deposit powder on your face. It's worth remembering though that I am a year older now, so oil production would probably be slowing down now anyway (I'm nearly 20).
I'd recommend the Body Shop ones if you wear make-up because they're very good at absorbing oil and don't disturb your make-up (I don't wear any now that I don't need face-powder) - you'll definitely want to cut them in half though, considering the price. Don't be too intimidated by the price though, since they should last about as long as a setting powder and are much, much better for your skin and a lot more convenient.
The Superdrug ones are a good place to start if you're on the fence since they're only 50p, but they are covered in reddish powder which won't come off if you just blot but may rub off very slightly if you forget and wipe instead. Also, I have no idea how they do with make-up, obviously. Seem popular though!