Harman Kardon amps


I have a HK signature 1.5 for my fronts RF7ii
im trying to decide another Harman Kardon amplifier for my center channel RC64II and surrounds (4)RS62ii 
i can have HK Signature 2.1 for $300
or HK Citation 7.1 for $700 
anyone has experience with those two amps ?
lordrootman