Benchmark of Stock ROM Android 4.1.2 is Just 1500+
Benchmark doesn't mean anything. I mean even if the do, there more than a benchmark number to the every day use.
It's also about stability, smoothness, memory management, multi app use.
I truly think 4.2.1 stock is the most stable of all of them. Add a good kernel to it, and it's like google on steroid. Again, we are talking 512ram here, so don't expect too much. People expect different things from their phone. I don't play games at all, but I stream music via bluetooth constanly while I use navigation. Imagine these 2 memory hogs running at the same time and someone is calling you.
4.2 for me personally was a bit buggy. 4.3 is much better, still not as good as 4.1.