Lisa,
I'd wait until after DEMA, just in case someone offers a new product in this space for divers. Otherwise I'd go with the ResQLink Plus. It really is built very well and the unit is buoyant, has a strobe and is only several dollars more after the rebate.
The PLB registration system is very simple and a HUGE benefit. You register the device once, however, you are encouraged to update any important information about your whereabouts and activities. For example if you were planning a trip to a remote location in the Indo Pacific you can login to your SAR account and provide all of the prudent information. This is a big time saving benefit for SAR. If you provided that info and they get a ping that matches the location you can bet they won't waste any time trying to determine if it's a false alarm. Plus they will have the contact info for whoever you're diving with.
I use a different canister than Don, but as long as it's water proof you can't go wrong.