Of course, there is no best rom, but there may be the fastest.
Now in the presence of Exposed, less people care so much about customization features that come within a ROM. Speed, stability and battery life are the most important. JustArchi’s optimizations take Android’s performance and efficiency to a whole other level. JustArchi’s optimizations apply during the compilation process of the ROM and hence take effect from the bottom level of the OS. XDA developer Satyr007 builds this kind of ROMs for the Nexus 5. JustAchi’s optimizations can theoretically apply to any ROM build, but right now only these special builds of Mahdi and OmniROM are available with the aforementioned optimizations. Feature-wise they are identical to their original/official counterparts, but they are SO MUCH FASTER!! I’ve been using this version of Mahdi ROM for a while now, and never experienced any lag AT ALL. And if you’re still concerned about features, these ROMs have you covered as well.