Yes, basically the same machine. Ecal. are using the same electronics in a different configuration. To waterproof a Sov. will cost you a few hundred bucks plus for parts to do it right. Current Sov XS-Elite prices are running $375-600.00
If you look hard enough a used Excal. will run from $500 plus depending upon the age and what comes with it. I think it also has a weighted searchcoil
If you going to beach and water hunt save up for an Excal.
If your more into inland hunting, beach sand hunting and occasional shallow water hunt and know you are not going to get the box wet, get a Sov. You could always hip or chest mount the box.
I had an older Sov. XS2a , rear mounted, a meter and a weighted Excalibur Sea horseshoe searchcoil.
It was a deep sucker, no problem finding dimes at 10" in the red clay soil of Georgia. I actually liked it better than the Elite I owned a year before that. But it was heavy!! I was going to waterproof it but, changed my mind.
My elbow was good for about 2 hours of hunting before it started to get painful.