i think that what every you choose it will be awesome!!!! A kpop concert would be nice and the fans really connect in the fan chants. but a fan meet is different and has different stuff to it. make the best choice for urself.
I would go to got7 and I don't know shinee that well (except for their songs) but I know in got7 mark (and Jackson) speak English so if they are having a fan meet also I would go cause it may be easier to communicate