well i don't use reins much as we are either in buggy/car but when we do walk somewhere, i use these ones here which have been brilliant as my DDs are happy to put their "backpack" on but i can grab them when and if the need arises.
get nothing but "where did you get those?" when i use them!
i can see why some people react negatively to reins, i see some (usually grandparents i think) people in the park, with their kids on reins, and i do want to say "oh, please let them run!"