in the summer only the glacier is open. its pretty flat but the park is ok, saas fee's is better, zermatt's is a bit limited. the nightlife is pretty fun but expensive. there is a mcdonalds for cheap meals (by swiss standards) and no cars. the matterhorn is pretty imposing. that is the best i can give you at the moment, it's late here.
zermatt is decent but as mentioned, saas fee is closeby and it has a better park ....
+there are also a lot of summercamps and infrastructure(tramps and other leisure activities) at saas fee while zermatt is a bit lacking in that department ...(saas fee also has a really cool via ferrata)
but... in zermatt you're at the foot of the matterhorn, quite possibly the most beautiful mountain of europe and you can do really cool glacier walks from zermatt, for example you can walk up to the schonbiel hut at the foot of the matterhorn and spend a night there, it's really pretty cool !
so if you're a parkrat and strictly going for park/freestyle, i'd advice to go to saas fee
if you're more of an alpine adventurer, go visit zermatt and experience the alps for what they really are!
if you have some experience in glacier walks, you can do wonderful multi-day tours in the area, you're basically in the heart of the alps, you could do a part of the haute route and walk over to the town of arolla (nighting in the schonbiel hut and the bertol hut) then take a bus and train back to zermatt (i did the same but from arolla to saas fee, which is even further, and it was like 25euro )
really beautiful place imho, that area is definitely the most beautiful of the alps
This too. I went to saas fee but drove with my parents to zermatt for a day and hiked around the matterhorn. Definitely the coolest place i've ever been. If i were you I'd try to at least get a day at zermatt