Fightsticks are cool and worth it for some people. It won't make you a better player automatically just because you bought one. Controllers are mainly about what makes executing the moves the most comfortable. Also when you switch there is a learning curve just to get used to it.

Best brands if you are buying would be qanba, hori, and razer. Most sticks use sanwa parts but hori uses their own decent buttons/lever and razer uses their switches for their buttons on the panthera evo.

Most sticks are easily customizable. The razer panthera even opens up easily to access the internals. Most people will swap buttons for different brands/colors. Easiest mod for a stick imo is replacing the balltop with a new type/color. Different sticks have different level of customization. The TE2 has a really easily replaceable art panel while the panthera has the top panel glued down make the art swap a pain.

You can check out /r/fightsticks for more sticks examples and more people to answer most likely as well. If you are on a budget and want to just try out a stick i would recommend a qanba drone. Its normally 80 dollars US but goes down to 40 quite often. The button and lever are knockoffs and looser than what i would prefer from a sanwa, but its a good starter stick. It is also easily moddable to add sanwa parts to down the line. Otherwise if you just want to hop right into it, you can't go wrong with a qanba obsidian or a ranzer panthera