One thing i have noticed with the sensation is that we stop developing the current ROM as soon as something new comes out and that leaves every ROM half stable and what i mean by this is that e.g. Viper 3.1.2 hasn't got great battery life and it could certainly be improved but because sense 5 is out we're just skipping the 3.1.2 build and jumping on the sense 5 bang wagon without fixing that issue and that's what I have noticed with every ROM, so why don't we all ask the developers not to build another ROM until the current one is stable, if you get what i am trying to get across.
1-Virtuous ROM and HyperNonSense doesnt has any Kind of lag in it you should give it a try(all Skimmed ROMs are great)
2-I'v been using for the last week miui v5 based on 4.2.2 and its really smooth specially when being compared to other miui versions on other more powerfull devices
3-All JB up to 4.2.2 on all devices start to lag a week later because of accumulated carp files all over system so get FSTRIM from playstore to fix it
4-Try using multiswap or triple boost ,things will get better for sure
5-The device is old but because of great developers we are being able to get all versions of newer JB on our devices so dont expect much from a completely new ROMs, if you are going for something stable try something with no developing at least 2 months