There's so many variables in tax, it's almost impossible to give a simple answer on which way is better. Some of the things to consider (and I'll try to expand on the points, but again, no way can I be all inclusive)
1. Are you going to be subject to CPP premiums? If you earn the money yourself in your rental portfolio, there's no CPP premiums. This saves approximately 10% (since as self employed you'd have to pay both halves at about 5% each). This is also true if you let the corp pay the taxes and pay yourself with dividends. Only employment income (whether self or not) is subject to CPP. Now keep in mind that there's an annual maximum earnings (can't recall exact) somewhere around 40-45,000 per year. After that, no more contributions. If you're earning income from elsewhere and already max out in the year, it's no longer a concern.
2. Do you WANT to be in the CPP? Again, something of a personal question. Some prefer to have that ultimate safety net, just in case everything goes sideways. Others view their portfolio as their retirement and are confident in it. I always tell people they shouldn't loose sleep over that classic concern over whether CPP will be there when we retire, as it's well funded and should be good to go for decades.
3. Are you subject to any income tested clawbacks (Old Age Pension is kinda the biggie here). If you take a wage, or even earn the income yourself, every dollar that you earn is counted as exactly that.... a dollar. For instance, before you have to pay back any OAP, you have be earning more than around $65,000. If you're getting close to that, dividends from a corp may be a bad idea because of a tax calculation that treats every dollar of income as $1.25! Now, this is offset by a later tax credit, but not until AFTER you potentially have to pay back some OAP because you earned too much (even though you didn't).
4. Allowances from a corp. Tax law allows an employer (a corp) to pay an employee certain allowances without having to track EVERY LITTLE THING. If you're self employed, you don't get that option. One common example is vehicle costs. You drive around to review, manage, show, clean, repair, and sell your properties. A corp can pay a tax free allowance (currently about 52 cents, have to double check) for every kilometer. As long as you track those business kilometers, that's it. If you're self employed, you have to track EVERYTHING. Every gas receipt, oil change, repairs, maintenance as well as the number of personal and business km you drive in a year, and then you can deduct a prorated portion. Pain in the butt! Added note, for those who have enough properties, and think they can just write off the entire vehicle, you still need to track the kilometers to prove they're business, and you better have a seperate vehicle for personal use. Pain in the pocketbook!
5. Costs. Having your taxes done if it's in your own name is easy and fairly cheap. Lots of people can even just do it themselves. Corporations are a whole other animal. Tax return is completely different, plus there's usually annual costs for filing your annual return with provincial registries, minute book maintenance, etc.
I could go on and on, but frankly, my hands are getting sore.
However, let's not forget the one main thing with a corporation, and that's limited liability if something happens. A lot of times, the banks are not going to let you off the hook on a mortgage (if they even give a corp one, little harder to get) as they've probably got you to sign a personal guarantee, but if someone breaks their face on your property and sues you, having the properties in the corp can protect your personal assets. That's more of a legal matter which I'm certainly not an expert on, but wanted to throw it out there.
