The drive is unbelievably beautiful in parts. We were surprised at the amount of wildlife around (bear, dear), and the views. We did a fairly fast trip from Banff to Jasper over about 5 hours with short stops along the way. It was pretty tiring, it is a fairly busy road, and there is a lot going on with traffic, and groups of families getting out of their cars on the side of the road to look at the bears in the bushes nearby. Seriously. We didn't see anyone get eaten, so it must be all good.
There are two main issues you face. Firstly, the convoys of campervans tooling along nose to tail at a constant 25mph who overtake you every time you stop, and then you get stuck behind them again for 20 minutes unable to pass as it never seems to occur to them to actually look in their mirrors and see the line of 300 cars strung out behind them. They are like the pace car at an Indy Car Race, but you never seem to get the green light.
That makes you not want to stop, as you see them in your rear vision mirror approaching from behind at their glacial speed. Overtaking lanes will usually see two of them side by side fighting it out for supremacy, and everyone else still sitting there behind them in despair. If you do ever get past, you will immediately see something worth pulling over for, and you are back at the back of the line. After about three hours of this you are frazzled, and just keep going. You could see Aliens meeting Elvis and handing out free money by the time you get to the half way mark, and it still wouldn't be worth stopping to see.
A complicating factor is the locals who use the road as a shortcut between nowhere and somewhere else, who seem to be totally oblivious to things like speed limits, other drivers, blind corners, double white lines, waiting their turn, turn signals, waiting for oncoming traffic, etc. They just blast through everyone at high speed without a care in the world, so it pays to check your mirrors before overtaking. Generally speaking, they consider anyone doing 20 over the limit to be holding them up unnecessarily, and will give you a brief finger as they disappear over the horizon at about the same speed as the Millennium Falcon.
Secondly, the Park Service isn't too keen on clearing vegetation back from the viewpoints. You can pull up to a marked viewpoint, but all you can see is a 30 foot high wall of weeds that has grown up over the past 20 years and never been cleared back. You are then left trying to stop on the roadside to get glimpses through breaks and down gullies. Some areas are good, but there is often no point stopping, as you can't see anything but groups of confused people looking around trying to figure out what they are supposed to be looking at. Some places that would seem to be crying out for a place to pull over get nothing, and other places that are just a little bit nice have pull offs where you could host a World Cup soccer final. It just seems to be poorly organised, Eh?
To see everything you need to drive one way one day, then turn around and drive back the other way the next day. Unfortunately, that will probably require you to stay in Jasper. Sorry. I recommend doing it with a Zen-like level of patience and love of campervan drivers, or as a passenger loaded with Valium and a commitment to say 'NO' to road rage.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.