Sam,
I went to the 358GNR because I wanted something a little bigger and, to be perfectly honest, a little "different" to hunt deer with, in a rifle configuration (while staying within Indiana game laws). Mine is an H&R SB2 frame that started life as a 22" 357 Magnum barrel. Gary reamed the chamber out to fit the larger case and I'm working up loads that will be suitable for deer hunting, here in Indiana.
Personally, I can't say that I would ever want to shoot a revolver that generates more power, at either end of the gun, than a hot 45LC, but to each his own. The thing that concerns me about the 455GNR is that it is a bottle-necked case in a revolver and we've all heard the stories about set-back and locked up wheels. I guess if it's designed right, it will work. I don't mind a little expense and work to get better performance, but I'm not sure if that logic applies to revolvers, for me, personally. In your shoes I'd either stick with the 45LC or go with the 454, if you really want more power.