How much of a P.I.T.A is a tank bag when it comes to filling up gas?
Depends on how it's attached. My strap on one is pretty easy because I just loosen the straps and push the bag to the side to get access to the filler.
On balance I would say that it's easier than taking off your rucksack to get to your wallet.
Luggage on a bike is always a compromise and it also depends what you are carrying and how you get access to the stuff packed away in them during the ride.
Bottom line, to be the least disappointed/frustrated with the chosen solution you first need to work out in your mind what the functional priorities are and then start from there.
So:
- Tank bags are pretty easy to use, simple, versatile and relatively low cost but there are many different sizes & types of attachment methods, so that's where you focus your research.
- Top boxes offer security and weather tightness but are more expensive, heavier and generally more permanent.
- Panniers carry the weight lower but some make it difficult to filter in traffic and can make the bike difficult to get on and off, hard shell ones are heavy but secure and easy to remove....etc....
My choice these days always starts with either a small/medium sized tank bag or a tail pack. If I need more capacity, I first reach for my waterproof - roll top tube bags and build a christmas tree behind me (lol....) and if that's not enough I swap for a bigger tank bag.
I've been riding bikes for so long I have all types of luggage systems that I can adapt to fit whatever bike i'm riding. I've got top boxes, tank bags, roll-bags etc...
I used to have hard panniers and soft panniers but they are the only items that I decided to sell on or give away in recent years. That's not to say that I would never buy again, but they aren't my preferred option and they take up space at home.
I used to use rucksacks all the time when I was riding my motorbike to college & uni, but back then I wasn't very safety conscious so wasn't thinking about getting my arm ripped off or doing face plants on the tarmac if I came off etc....
My advice is just think about it and do your own research. Be prepared to learn in practice what works best for you.