Best ROM for Xperia Neo L topic

So my friend has Xperia Neo L (MT25i) and her current rom is so lag.
She know that I know how to change roms but she doesn't know that I only ask here lol.

So guys what is the best rom for this phone? Something that does not lag even tho it has so many apps. (I saw her phone. Lot's of apps lol)
Any professionals out there? Come out for me please.