The phones to be compared are:
ASUS Padfone S Plus (April 2015) vs. OnePlus One (June 2014) vs. Asus Zenfone 2 ZE551ML (March 2015) vs. Xiaomi Redmi Note 3 (November 2015) vs. Samsung Galaxy A3 A310F (December 2015).
For price per performance, Padfone S Plus has some advantages such as: additional docking for larger display and battery, microSD slot, large RAM, still powerful CPU, NFC connection, and useful USB-OTG.
OnePlus One has good advantage in superior camera component and larger community support for custom ROM but lack of customer service office.
Zenfone 2 is the best phone in its price range, larger screen and RAM also better camera than PFS+ while have the same features, and better than Redmi Note 3 except for fingerprint feature.
While Galaxy A3 is out of equation.