Side by side Duplex OR lavel1/level2 Duplex

[Aditya Soma]

Hello Everyone

I hope everyone is doing great.

Yesterday I was taking to a seller(Also REI with 40+ experience) in Windsor Ontario, he suggested me not to buy Duplex with 1 unit on top of other unit, he said always SIDE BY SIDE Duplex's are best

Couple of reasons he gave why duplex with 1 unit on top of other are not good for investors:

1) will never have appreciation OR very low appreciation

2) will always have tenants complaining on each other 

3) low rents

how far is it true?? 

Thank you very much in advance for your feedback 

Aditya Soma