I am also in the market for one except I'm looking for a 253LA. I just don't see the need for the 300 if all you'll be using it for is salmon/steelhead.
253 can hold about 180yds of 15lb line which is more than you'll ever need; the reel is lighter, more compact and cheaper. In my opinion, the 300 just looks too big and has huge capacity even for heavier line, which again could prove unnecessary depending on what you plan to use it for.