As far as downtowns are concerned, Regina does have some nice looking office buildings, but the street level, aside from Scarth between 11th and 12th, is dead. Saskatoon has an enviably vibrant downtown, especially along 2nd Avenue and 21st Street. 3rd Avenue is also catching up, especially the area between 22nd Street and 20th Street. The theatres, restaurants, pubs and clubs downtown all keep Saskatoon's downtown hopping (not to mention the other retailers from Midtown Plaza on).
The other thing to consider about Saskatoon's downtown is that it doesn't stick out and look as impressive as Regina's for one big reason: it's in a valley. No matter where you go in the city, you travel up from the downtown (this is especially noticeable when downtown and looking up at the east-side river bank or when traveling down Idylwyld near the Ramada). Saskatoon's tallest buildings and Regina's tallest buildings are all around the same height, but Regina doesn't have Saskatoon's topographical features.
Here are a few photos of Saskatoon's downtown I've taken over the years (including a few different angles of the skyline):
The photo below was taken from the Warman Road overpass over Circle Drive/45th Street. Sorry about the forest fire smoke.
All photos taken by me. I've started uploading a few pictures to a
Flickr account if anyone is interested - I'll get a few more street level and University pictures up there later.