Bob,
The Explorer SE and SE Pro are identical detectors other than the decal on the side and the coils (the SE Pro has the Pro coil which can always be added or one of the after market coils used). There were some subtle differences in the Explorer II and SE / SE Pro and many of the people that have used both see little if any difference in the field. There does seem to be a slight difference when beach hunting ocean beaches with the edge going to the EX II . . . . . hard to explain why, just something that a number of users have noted. But regardless of if you opt for a II or an SE, the Explorers have an edge over the E-Trac in this application; i.e., wet salt sand.
As a matter of fact, there are many very successful beach hunters that still swing a Sovereign. I have mine setup with the WOT and can cover a lot of ground without tiring and have hit some pretty small targets with that rig in the Myrtle Beach - Charleston section of the east coast.
Andy Sabisch