Anyone used hybrid AHD camera-DVR set-up?

Hello, i'm wondering has anyone used an exisitng CCTV set up with old cameras or dvr's for example with a digital DVR.

What kind of resolution can you get? Is it limited to the camera tech, or the dvr tech.

I have an analogue set up but was wondering how good the hybrid DVR's actually are? I have come across this - www.rfconcepts.co.uk/ahd/dvr-ahd.html which ssyas the quality is there, but has anyone actually used hybrid's before?

thanks

When adding HD-AHD cameras, please check and test out the cable length that HD -Cameras can go without getting their video quality poor. 720P cameras can go further than 1080P.