hi, y'all
I too am struggling with this
want to preserve the original looks of the bike.. but also want practicality if I'm going to spend 1 or 2 nights in a far away hotel with my wife, so need to take (small) baggage
usually the wife "takes the hit" carrying a backpack; but if it's heavy (her things, obviously, not mine) it's bad for her back
but I don't like top-cases which in my opinion disrupts the looks of the FJ
also, my favorite choice - hard case side panniers - are too expensive for the FJ (ridiculous prices for the bars + cases)... and the back blinkers may have to be moved, which I don't want
soft side panniers are dangerous in my opinion, as they may get into the wheel/tire... nope nope
soft top-case... also disrupts the looks of the bike
so the last option is a tank bag... magnetic or straps... with or without a tank cover
tank covers also disrupt the bike looks, especially the all black ones... but they also protect the paint of the tank against scratches... I saw one brand new for my FJ in matching color... but it's very expensive... and if down the line I decide to sell the FJ and buy a completely different bike... I can't re-use the tank cover, as it's made to fit the tank
tank bags with straps look so complicated to install/remove... tank bags with magnets look the most simple choice: install-magnet on then uninstall-magnet off... with the option of putting a cloth between the tank and bag to protect against potential scratches even more
there's also the capacity... having a small tank bag is worthless for me - might as well not to buy it at all - so it has to be at least the size of a normal backpack, to carry at least a 1 night-hotel baggage for 2 people... I'd say the minimum would be 25 litres
I know there's big tank bags that also expand... but even in their normal not-expanded form... can you still see the clocks? (especially speedometer and fuel gauge)... I wouldn't want to get a ticket, thinking I'm peacefully strolling on the highway at a safe 62 mph but then realising I'm actually at 87 mph!

so the big plus on a tank bag is that even if you sell your bike and buy a completely different one... at least you can still keep the bag and use it on the new bike... so it's a good investment down the line, that will last you as long as the bag itself lasts
(of course it would be way simpler if the FJ had OEM integrated hard side panniers)
regards