Okay, I'm going to break this down into aesthetics and function:
Aesthetics 8/10
I am somewhat underwhelmed by the design - my initial reaction was "it's a straight tube?!" It could've used some curvature, either with an shallow arch across the river, or with some curved entrances on the ends to break up the straight lines of the main shape. On further reflection, I think it's going to look pretty nice close up, with the downtown in the background. I'm already thinking of photos with Canterra / Centennial in the background. From the inside, if it comes out anything like the renderings, is going to be spectacular. I hope the LED lights are pointed to the center beam so they don't reflect off the glass at night - need to be able to see out.
My favorite spot to sit and meditate in Calgary is the west end of Prince's Island, right beside where the bridge is to be built. I'm thinking, net positive addition - but Zen is a fickle thing, and I won't really know until they are done building this thing and I'm sitting there contemplating it.
I'm okay with the color. At some point it will end up getting painted, but by that time my bet is the vast majority will want it painted red/white "just like the original".
Function 9/10
I give the bridge high marks for having separate bike and walking lanes. Not only that, but take a close look at the track - The cyclist lanes are depressed into the bridge deck, with (drainage?) along the sides further discouraging cyclists from wandering over on the pedestrian part of the bridge. I'm guessing that the width will be just wide enough for a city vehicle to use this as a crossing for maintenance, emergencies, etc. This may be the first pedestrian bridge in the city where the speed limit will NOT be "walking" or 10km/hr. BRAVO!
The glass covering will help keep snow off of the bridge in the winter, and the glass will warm things up a bit on a calm winter day, providing a nice greenhouse effect. I don't think it will be so severe in the summer, as there is almost always enough breeze to provide ventilation.
I'm not fond of the approach ways to the bridge though - on the north side, we have sharp 90 degree turns - turning that into curves, along with a bridge design to support a wider entrance, would've helped. I don't know WTF they are thinking on the south side. The under bridge path should be for cyclists by-passing the traffic jam that is likely to be up above where pedestrians and cyclists meet from all directions, but that's just my guess. I would say it shouldn't be worse than any other blind corner in the pathway system as at least it's level, and of sufficient width. The approach ways to the bridge on the south side seem to constrict, then open to a circle, then lean on to the bridge. That could just be the perspective of the rendering though - I'd like to see a top down view.
Overall this is a reasonable looking design with some strong practical elements that will please both daily commuters into the downtown and casual folk looking for a memorable shot of the city.