For me: I tried every build (from 1. to 5.) and I can easily say that ROM is really smooth because of no FPS capping like on other CM11 ROMs.
Build no.1 Was the beggining of development of CM11 for our little Pico.
After a week using it,I found it very smooth,snappy and stable. Everbody started to using it. It showed how KitKat is used by legacy devices.
I found only one bug. Rebooting. After every reboot,my data gets lost and my phone starts again. This was very annoying so I was just waiting for a newer build.Finally,Arslan released a new build.
Build no.2. Devs are making huge progress by fixing almost all bugs. But they are still showing on testing. ROM keeps to be silky smooth. Bugs I found are: wallpaper managment.
Everytime I reboot,my wallpaper gets zoomed for some reason. Also,devs fixed the data loss problem appearing on previous build. I was very pleased to use the ROM.
Build no.3. Kirmani Arslan,Sachin Thomas and Terminal Unity (known as GalaxyFreak) are made ART compiler avalible for Pico users. Thats a huge suprise for Pico users. Also,they upgraded the Android version from 4.4.2 to 4.4.3. Cool things about this build are:they moved from ARMV6 sources to ARMV7. That makes our phone snappier in form of performance and we can use ART! Also,we got the new blue dialer appearing in 4.4.3. Bugs I found: Really annoying graphical glitches, They are appearing as lines on screen when you touch it. I was hopping to fix that and VOILA! They were fixed in next build.! But not completely.
Build no.4. Devs put CM upstream so that made ROM pure CyanogenMod experience. Also,in build no.2,S2W and DT2W toggles were fixed so you could use them but a bug showing with using them. You can use them only if both of them are enabled. They also put a soundimage of HTC One M8. Problems (not bugs) occuring are: Sound volume at call,speaker volume at call and random reboots. That was not so annoying because reboots happened one in two days. But the call saund was not so good.
And latest BUILD no.5. They made huge progress. After putting it to CM upstream sources and fixing all display bugs,now they made sound quality great (but volume still remains the same). Thats not all,they updated Android version to latest KitKat: 4.4.4. That brought OpenSLL fixes,new web search engine and really cool CM wallpapers.Almost no bugs at all. Finally,they managed RAM usage to make phone more usable and making it as my daily driver. Now it is smoother,snappier more stable and no bugs. You can multitask more because of RAM management.
Comment your experiences!