I've been saving up to add two G5s to my Piper Cherokee instrument panel and remove the entire vacuum system. I was going to make the upgrade the next time a component in the vacuum system needed attention. But, RC Allen has just come out with the MINI6 which has definitely caught my attention. It combines the entire six-pack into a single digital instrument. It looks like Aircraft Spruce will start shipping them October 15th. It has a replaceable backup battery and built-in magnetometer. I also considered the UAVIONICS AV-30-C (certified version), but my biggest complaint is that it doesn't currently have an option for a magnetometer. You have to periodically reset the DG just like the old vacuum system. At a current price of $3250 it is more expensive than the G5 or the AV-30-C, but you only need one unit to remove the entire vacuum system. It will be interesting to see the feedback from the community once owners start installing these units.