A few random thoughts.
Don't worry about easy removal. Might make sense in concept, but in practice barely ever leave the bike unless for storage. They're super awkward to carry off the bike. Inner bags are much more convenient for taking your belongings on and off the bike. Pro tip, Ikea tote bags are indestructible, waterproof, fit panniers perfectly while not taking up any space themselves, cost the massive sum of $1.
If you're not camping (camping for me takes up 60L on it's own), a top case plus 50-60L duffle across the back seat is an amazingly functional and cheap setup. Top case for items you want easy access to and don't want stolen. Duffle for everything else. Makes for getting your stuff to and from the bike super easy and convenient. If you don't need massive space, this is the best setup IMO.
If it must be panniers, get top loading. Makes accessing things much easier without having to take either the pannier off, or empty the contents. Also have the option to strap dry bags or stuff to the lids. I run a 30L dry bag on top of each pannier when camping. I would prefer going with a recognized name brand, versus something cheap that someone makes in their garage. If you need spare parts or support in the future, I'm much more comfortable knowing the company will still be there.
For my money, I went with a Givi Trekker Outback pannier/top case setup. After a crap ton of research, they were the best option for me. Out of the brand name stuff, it was the cheapest option. Panniers plus rack can be found for about $1000usd. Bumot's are $1200, Touratech's are $1500, Jesse's are around $1500. The cheaper pannier systems (Happy Trails come to mind) are $700-800usd and from appearances don't seem nearly as good.
I didn't mention soft panniers because I don't have any experience with the newer stuff. For me at least, unless I'm doing hardcore adventuring, I'm staying with hard luggage.