.18 build is alot faster then build .10... once thing i did notice big time from 4.2.2 was that 4.5 picks up EDGE a hell of alot faster then 4.2.2
with build .10 my issues were it was somewhat sluggish, BBM would ask me to update my contacts with my new PIN (even tho it was the same device) everytime i did a hard reset, and required me to do an advance restore of just my BBM. also there was a major memory leak issue as well, which i think has been fixed in .18 build from what i can tell.
Signal dropped a few times but was back up within 10 secs or less. never dropped while in a call
build .18 has alot of improvements just some minor tweaks needed from what i can tell so far, tho i have had the signal drop once in the few hours its been on my device...
i will update if there is anything else that i encounter