Hey,
There's a huge thread on redflagdeals about these phones. Also gives tips on which providers you should go to. I can't get on the thread right now (at work), but you can find it through a simple google search.
I have the Mi Max. Albeit it is not the Redmi but these phones are pretty amazing for the price. Mi Max's performance is similar to a Galaxy Note whereas a Redmi has similar performance to a galaxy s series phone. My only concern about aliexpress is the shipping time. Currently CBSA has been looking through most packages that come in through the Vancouver area for drugs. There's also a huge thread on redflagdeals about the shipping time from Aliexpress. Be prepared to wait 2 - 3 months.
For $200USD, it's a steal in my opinion. Comes unlocked, works with all networks in Canada and (for the Mi Max) has LTE. Unsure about Redmi, but specific models ( I think 4?) has LTE.
I would say these phones are perfect for BYOD plans like PM. You can recover your cost fairly easily since the phone is affordable. Most other BYOD plans give you a 10% discount.
I hope this helped! Best of luck in your decision.
