I went there yesterday. The trainfare zurich-brigg was 160chf and then visp-zermat was 66chf. (i guess you can buy them as one, i didn't realise I could buy just one ticket).
the train from zurich-brigg was very boring, no good scenery, . the long tunnel was an experience/impressive but its just a tunnel...
From visp (rather than brigg) I took the glacier express. I dont know much about trains but it seemed a narrower gauge than normal with a cog in the middle. train was wobbley

(the previous day I took the glacier express from chur-st moritz which was a fantastic trip, so maybe i'm being harsh).
the route is up a single valley, no big tunnels but the valley walls are pretty imposing. lots of olde worlde swiss houses to photograph.
I arrived in Zermatt around 12noon, wandered around for 10minutes (it was -1 and snowing) looked into the gornergrat ticket office and it was packet out with the blue rinse mob, so wandered around some more. my impression was lots of cheap hotels, a mcdonalds (why??) and funny electric taxis (golf carts maybe?).
Went back to the gornergrat ticket office and stumped up the 54chf return fare.
Sat at the front of the train, by this time heavy snow, visibility down to 10 meters and getting colder

. A good 30minute journey to the top. At the top, it was minus 7, couldn't see a thing and some god awful shopping mall (with a telescope on top??) ..tell me.. who the **** wants to by a handbag 3200meters up a mountain???
I will try it again in the summer, but hope never to go there when its cold