Aftermarket backup camera system in Montreal

I've got a car with a 2DIN stereo compartment. I see a lot of aftermarket 2DIN car audio kits which include a backup camera for less than $150 (I'd pay more for one with an OLED screen and USB port, but don't care about "smart" features past bluetooth and a radio). Can anyone say if there are any drawbacks to these kits compared to one that comes with a vehicle? To save trouble, are there any dealers in Montreal who have an up to date selection and will install for a not bad price? Thanks!