I have both the 1GB and 2GB version (both of them had the same version number which is 2014817).
Prior to used the 1GB version, I bought it when it is first launched in Jakarta, Indonesia. At first you are right, it is so laggy as hell..! I even almost throw it to the garbage! LoL
But after a few software updates the performance just got better and better. It is highly recommended to install Xiaomi.EU ROM, stable or weekly doesn't matter, both of it are stable enough for daily use.
Right now, I'm using the 2GB version (redmi 2 enhanced). I bought it just because my 1GB version had a little dent on the corner of the screen, because I dropped it on the floor. Now I gave the 1GB version to my cousin (he is still use it until today as his daily phone).
Performance wise, to be honest, I don't really notice the different between the 1GB and 2GB version for daily use (chat, browsing, camera, social media) as I never use my phone for gaming anymore.