After trying Uber once I was immediately hooked and now it's the only way I take a cab. I love the fact that everything is electronic and it gets charged to your credit card because you don't have to worry about making sure you have enough cash on you when you get in the cab. You are also given your driver's name and contact information which can be mighty useful at times. On one Uber trip my phone fell out of my purse in the cab but I was able to get in touch with the driver and I had it back 15 minutes later.
If you're taking it during peak periods (ex. Saturday night) you might have a tough time getting a cab but that only happened to me once. Usually they come quickly if you're in a centrally-located neighbourhood (Downtown, Plateau, etc). You cannot get Uber at the airport though from my understanding. I also have only ever used Uber Taxi so I have no comments on how it compares to UberX.