I have owned the Simaudio Moon I-5 and Electrocompaniet ECI-3 and liked them both. Just as Woodman mentioned, the I-5 sounds stronger than 70wpc, but so does the ECI-3. However, I don't know how either would fair with planars. The I-5 has the more neutral presentation, and is also more transparent. The ECI-3 is a bit smoother. But I should add that they sound very similar, and this really surprised me. If you get a chance to audition the Electrocomapniet, try to listen to the ECI-4 which is their 120wpc integrated.
The market for integrateds has never been better. There are many many great amps out there. Enjoy!!