The Aspen Avionics E5 EFIS display has finally received FAA STC approval but we will have to wait some more for the EASA STC. Just like the Garmin G5 the Aspen E5 is not TSO approved and must be installed in accordance with the FAA/EASA STC.
The E5 is a downscaled version of the EFD series and lacks OAT, backup GPS and some of the more advanced features found in the EFD1000PRO. Pricing of the E5 is about $5000 and $6000 with ACU module (required for autopilot connection) which make the E5 it slightly more expensive than the Garmin G5 ATT/HSI combination.
The Aspen EFD1000PRO requires that a backup attitude indicator remains installed but the with the E5 the attitude indicator may be removed if you keep the T/B indicator, this makes it possible to also remove the aircrafts vacuum system. For more information about the E5 system click here