Regarding the best market in Canada for investing, it depends what product you invest in. Commercial, industrial, residential, land development, etc., and whether you are a long term investor versus short-term (quicker cash) investor.
I can only really speak about residential.... I havent done commercial, industrial or land development.
I know Edmonton & Calgary have been quite appealing for investors fromother provinces (ON & BC primarily) as the price of entry is much lower here than Vancouver or Toronto for example. We also have more inventory available to choose from, and less competition for those homes, which helps keep projects more affordable for investors.
For buy & hold - go with the market you know and have confidence in. Also match your strategy to the market (do you want to buy rent-ready "turn-key", or do the BRRR method? (Buy, renovate, rent & refinance?)
Many quick cash investors are enjoying fix & flip in the Edmonton area. That strategy also works in busier markets, but more $$ in for the same end result (ROI is lower if you have to invest more into the deal.) I know pre-sale condos that are then assigned seems to be a popular investment product in & around Vancouver. Not my strategy (or market), but I know it works well for those who prefer hands-off investing.
For buy & hold residential - I always recommend going the legal suite route. That has historically been easier & better supported in Edmonton than in Calgary (although I hear Calgary is getting better for suites.) Basically this gives you the opportunity for more total rents out of the same single family property. Would you rather rent out your whole house for say $2000/month, or rent it out as $1400 up + $1000 down? More rent, plus you are less likely to have total vacancy (risk mitigation with 2 suites under 1 roof.)
One observation I've had as a Realtor in the Edmonton area is that turn-key legal suites may or may not work for the traditional investor 20% down financing. If its recently renovated & legally suited, banks have a hard time appraising the property to support a loan because there aren't as many sold comparables on MLS supporting a purchase price of say $460k. When its vacant and advertising "rents may be $$$$ up + $$$ down + $$ garage"....the banks get skeptical and want to know actual numbers, not possible numbers. I have seen these scenarios where the banks want more down (25-30%, or they say they can only support financing a purchase price up to $$____, which means the investor puts down their 20% and an extra $20-$30k bridging the gap between contract price and what the bank wants to see.) If it truly cash-flows and/or works for that investor's model, the savvy investor will make the deal work, even if it means more $$ down up front.
If the unit is currently rented with signed leases in place, then the banks are more likely to support the higher purchase price as they want to know debt coverage is funded by the property, without the investor funding out of pocket on a monthly basis. If its fully rented and cashflowing, lenders can use some of the rental income to increase buying power. This would be a true "turn-key" rental. For this reason, its important to be working with an investor focused lender who understands what you are trying to accomplish.
If your investment model is more of the BRRR method mentioned above, then Edmonton has many great options. As Brenda mentioned above, there are many affordable suite-able bungalows & bi-levels available in Edmonton's prime rental areas. I can think of many investors who bought low (~$300k as an example), invested say $60k into reno's & suite legalization, and got an ARV appraisal for ~$460k. With 80% LTV @ $460k, this covers the costs of the initial purchase + renovations. These investors then have a property that cashflows well, has low maintenance costs (fresh renos = mostly new items and low maintenance), and will appreciate better than the fixer upper they started with. Plus with the refinance, they are into the property for much less than the traditional 20% down. The appraisals do show up in the mid to high $400's (in Edmonton at least) for fully renovated legal suites, although these rarely go onto MLS to be used as sold comparables (which banks rely on for financing approval purposes.) The savvy investors keep these as long term rentals.
Regarding values, on MLS I have seen that a legal suite typically sells for ~10% more than a SF home in the same area. Building that legal suite often costs the investor ~10% more $$ (& time). If you are flippng, probably not worth the effort. But, if you are planning long term, its totally worth the extra investment up front.