From my observation, if there are a lot of strong lights on the street, such as when you are riding among many vehicles, the reflective clothing you wear mingles with the surrounding lights so you are not so visible. It seems reflective clothing has the best effect when you are in the dark and only some few light sources are directed at you. Thus, neither too much light nor too little light would be helpful, and the few lights need to be directed in certain angle, so the scenario for reflective clothing to work is very limited. It is better than non-reflective, for sure, so good to be used as a back-up in case your bike lights stopped working (or were stolen). Just like the reflectors on the bike.