I installed a system two years ago. Purchased from an ebay seller named leviathan_holdings that I read about on this forum. Good quality, and has held up well. The cable connectors are good, solid screw together types. Not the cheapest out there, but I've been pleased.
If you think you will ever want to add additional camera's, look for a monitor with 2 or 3 inputs.
I have no connection with this vendor except being a one time purchaser.
I did a quick look at the offerings, and the prices have dropped in the last 2 years.
Fred
Fred & Vicki
Richmond Hill, Ga
2000 Holiday Rambler Endeavor/Freightliner/330 Cat
2000 Honda Odyssey toad w SMI Silent Partner braking system
Tire Sentry monitoring system