Hey, I'm a Canadian with an iPhone 3GS on Roger's network!
1. Rogers locks you in for 3 years. My advice to you is to figure out exactly what kind of services you want from Rogers at the start, because some changes to your contract cannot be made without renewing the 3-year lock-in. And yes, after 3 years, the phone is yours. It's also possible to buy out your contract early if your really want to switch networks or get a new phone. I don't know how much that will cost, but it's supposed to depend on how much time you have left on your contract.
2. In my experience, it's very unlikely that you'll go over a GB per month, so you should be okay unless you plan to be moving a whole lot of files or you don't spend much time around Wi-Fi. Depending on the other details of your contract, you're looking at a monthly bill of $70-80. You might be able to wrangle things down to the $60s if you give up enough other goodies.
3. The iPhone itself monitors data usage and call time under Settings > General > Usage, and you can reset it it monthly if you want to track that month's usage. I have sent 2 GBs of data on the phone in about 9 months. I think Roger's web site will also let you look up your usage, but I found it so terrible that I haven't been back there in a long time.
4. My iPhone has been the best device that I have ever bought, no kidding. All the power of the internet in your pocket, plus so much more. I use it for communication, navigation, research, taking records in text, audio, image, or video format. It's incredible the number of problems this piece of hardware can solve. I use it as an alarm clock, remote control, flashlight, level, and it's very helpful as a server administration tool. And that's not even touching on the games.
There are a few annoyances, but they've all been trivial to me, so far. I think managing data and apps on the device through iTunes could be a lot more elegant, I wish Safari would let me search pages for text (Opera Mini does, but it has other limitations). Some people don't like Apple's control over the App Store, but I have yet to see an app that I care about get blocked.
I don't have any hands-on experience with an Android phone, so I can't provide a good comparison with the iPhone's closest competition, but iPhone OS 4 seems to eliminate the biggest advantage Android has over iPhone OS.
One parting piece of advice. If you can hold out for 2-3 more months, new iPhone models should be on the way. Even if you don't want the new features (scuttlebutt says a much higher screen resolution), the 3GS should get a price cut at the same time.

"The worst part about these reviews is they are [subjective]--and their scores often depend on how drunk you got the media at a Street Fighter event." — Mona Hamilton, Capcom Senior VP of Marketing
*Image indefinitely borrowed from BrainBoxLtd without his consent.







