stock rom vs CyanogenMod 12 Android 5.0 Lollipop topic

Hey,
I've got rom stock on my s3.
The phone is slow and very short battery life.

Should i install cyanogenmod 12 - as shown here: http://www.naldotech.com/cyanogenmod...ung-galaxy-s3/

or stable cyanogenmod ?

or just stay with the rom version i've got on my phone.

Pls advice

tnx