I know this answer has probably been asked, before, but I'm just comparing 2 kinds.
Running on an ASUS P8Z77-V PRO
Price vs Speed vs Compatibility vs Real World difference.
Kingston HyperX (4x4GB) ~ $60
DDR3 1600MHz
9-9-9-27
-or-
Komputerbay (2x8GB) ~ $65
DDR3 1600MHz
10-10-10-27
Running on an ASUS P8Z77-V PRO
Price vs Speed vs Compatibility vs Real World difference.
Kingston HyperX (4x4GB) ~ $60
DDR3 1600MHz
9-9-9-27
-or-
Komputerbay (2x8GB) ~ $65
DDR3 1600MHz
10-10-10-27