I'm on the deodexed and debloated 4.4.2 rom and seemed to notice a better ram management than 4.1.2. That is obvious and many others can vouch for this. But I will say it does seem a little more buggy. Xposed is really needed to remove some limitations on kitkat. kitkat is snappier and more responsive. 4.1. is a 2 year old technology. A good technology but alot of speed, etc has been development in the last two years. jellybean was created when 720 and higher displays were barely on the market and same for RAM. There was alot of phones still active with very low ram. Kitkat just feels optimized more modern. Even though I think they could have implemented alot more features like IOS does every year. Especially when Apple made the leaps to Ios6,7,8.
I am running setCPU performance gov, xposed framework,modules, greenify, boot manager, and a few other non placebo apps. It is a little buggy I think but maybe its me. Link2sd keeps my internal memory at 800 mg to 1gb free so that also helps. And a lightweight launcher (currently Google Now Launcher) and I'm very happy. I just wished there was more development for modules like there are ios jailbreak tweaks. There are so many things I could do on my iphone that I would love to do on droid.
All in all I highly recommend kitkat over jellybean. I'm a poweruser but maybe somebody that just wants to text and make some calls and check weather or facebook every now and than may not be care