Its certainly "spotty" at best. I've sent packages out priority via my "click-n-ship" account while others have sent me packages 1st class and they would arrive faster than priority. I've also noticed that packages appear to travel one direction faster than the other (from my experience anyhow). Its also not mentioned often (I've shared this with many who've I've done deals with) but look into the regional rate boxes, you have to order them (free and delivered for free) as they don't offer them in the USPS stores/offices. The rates typically rival if not beat the flat rate sized boxes and you can stuff more items/stuff into them (i.e. their regional rate "A" sized is priced at the small flat rate but the size of a medium box).