Re: Electronic artificial horizons
I presume you really mean electronic and not electric horizons (the difference is lost on a lot of people).
I have come across the Dynon D-10 unit which uses solid-state gyros (RLGs) to provide the attitude and heading reference system in conjunction with a flux-gate compass to update the heading.
There has recently come onto the market a "pseudo-horizon" which seems to use turn-rate for bank and vertical speed for pitch. I see this as having potential dangers for mis-interpretation.
The Dynon unit has had lots of good reports and looks like a good option, especially for a small panel.
I believe the electronic gyros are essentially rate-gyros, but use electronic integrators and long interval averaging to correct for drift.