For "me", good and cheap panniers are those you buy once and get many years out of.
I believe I've found a set that qualify in my set of Ortlieb front and rear roller classics with matching handlebar and rack bag mirroring Tourist in MSN's setup.
Now that I've started filling my handlebar bag with my camera gear, I've added a Revelatedesigns Gas Tank bag for my phone, keys, wallet etc.
https://www.revelatedesigns.com/inde...ockpit/GasTank
Its sister, the Jerry Can,
https://www.revelatedesigns.com/inde...ckpit/Jerrycan has also been acquired in anticipation of my next long tour, with the intention of utilising it for tools, puncture plug kit and Stans liquid latex etc.
These in order to save me digging through panniers on the side of the road for things I require quickly to hand, especially in inclement weather.
I don't think there is really a wrong answer with regards panniers as it comes down to personal opinion but a set that's merely weather resistant won't work for me, but I understand others have different climates and priorities.
I would suggest a wariness of buying a set that you'll not be happy with as in my opinion buying the wrong set means buying twice which is rarely "cheap"