Here's my thoughts (personal opinion only):
Edgestar:
Pro: Currently priced at $499 with free shipping, sometimes goes on sale cheaper.
Con: Often plagued by out of the box QA/QC problems, questionable long term warranty, reported higher running amps in comparison, less desirable fit/finish (and in my build since it's a little wider it wouldn't have worked well verse the bit more narrow AR

.
ARB:
Pro: I like the dimensions/fit/finish better. Running draw seemed pretty low to me (I've posted voltage readings over a 6day run in the equipment forum, sorry no amp meter). 3year warranty. Removable lid.
Con: Currently priced at $799 with free shipping (I got mine onsale at 4wheelparts.com for $699 and picked it up locally).
Both units have a digital temp setting I believe. Not sure what the sound difference when running is between the two, if any. Vague recollection is the ARB definitely runs it's circuits off 12V and that when 120V is used it's stepped down to 12V, however one of the other manufacturers runs their electronics off 120V and when then 12V comes in it needs to be stepped up and thus there is an efficiency loss there??? (Definitely do your homework on that one as I can't clearly remember the details).
Long story short I choose to pay a couple hundred more for the ARB for the dimensions I liked better, fit/finish, possible lower running amps, and most importantly a solid warranty by a known manufacturer with good QA/QC.