Take your post to the GW owner's site. You'll get responses.
www.greatgrady.com
IMO, both models are good - just a matter of how you are going to use them. One is a 22 ft boat (Seafarer) the other is 24 ft (Voyager). One can carry twins, the other can't. One will be a significantly heavier trailering load than the other, possibly requiring a bigger tow vehicle.
If you are going offshore more often, having twins might be a consideration. Also, the Voyager would have a little better ride in rough water then the Seafarer, just because of its greater length and weight.
The Voyager will be more costly to run and maintain because of twin engines.
Bottom line, one is not "better" than the other. However one may be "better suited" for you depending on how you use it.