I've considered it, but the cost of converting all of our analog cameras (~14) to digital would be fairly high when I looked at the cost of the video encoders. The other option is a video decoder to use the new IP camera with our old system, which would cost a lot less, but not give us recording on the other cameras anyways.
Eventually, we would like to move everything over to IP but will probably hold off on any major changes until we know if we're moving to a new location in the next year or two.
I do have a computer to use for recording the IP camera.