Lever, has tones of leverage, getting your post nice and snug is easy. and you can undo it with out needing to be hulk.
i've had no issues with mine, and i use the non qr version on my dh bike too. light weight lil bit of bling.
If you want to raise and lower your seat get the QR (use it on my DJ bike to pedal around) if you want to set it and forget it, get the bolt on one (use it on my dh bike)