What are the differences between the two? In general people seem to go with the EX, but I haven't seen justification for the descision.
EX gets you more output and extension.
Looking at the specs it appears to be the same driver and amp. Is the only difference the larger box?
Yes basically the larger box is the only difference.... The larger the speaker enclosure the lower it can be tuned to and the higher the spl output will be.