OK, here's my 2 cents... Its a good excuse to get a benchtop mortiser.
Having said that, here's some "buts": it won't cut a totally clean mortise, it will still be a little rough and need a little (but not a lot) chisel work to smooth it out. Three inches is probably pushing the capacity of most benchtop mortisers, be sure before you buy. You probably will need to sharpen the hollow chisels before using.
On the positive side, they are fun to use, quiet, not much dust, once set up they just keep on cranking. Much more fun and safer than a router. And they make square holes!!! I hate rounding off tenons to fit a router hole.
I have the powermatic and I like it, but I wind up using my router jig, too when I want totally smooth walls on the mortise.
BTW, when I do a through mortise, with whatever technique, I always chop from both sides to avoid tearout.
Let us know what you decide.