>>4295896Using step up rings means no hood, that can be a pretty big deal. Not just for shading but also protection. Speaking of which if you do happen to bash a filter into something if it's on a large step up ring (say you've got a 72mm filter because that's your largest lens, but you've got it on a 49mm) then it's more likely to bend and crack. You've also got the hassle of moving the filter from lens to lens and keeping track of which size lens cap you need to put on and probably needing to buy and carry extras.
I wouldn't bother with them unless you happen to already have an expensive filter in too large a size for some reason, will be in situations where a hood isn't need or just don't have one, and just have a ridiculous number of differently sized lenses that actually need the same filters (for example you don't need a 10 stop ND to fit both your ultrawide and macro).
I wouldn't go with super cheap filters but you also don't need to go super premium. They're (usually) not lenses that change things in terms of modifying the light path, they're just flat pieces of glass, so all you're paying for is coatings.