I admit I haven't seen any of the after market lights in person, but from pictures the LEDs look small and not very bright. If you can take a picture in a completely dark room and see the individual LEDs, I can't imagine they'd be bright enough to be seen on a sunny day. See a pic of my OEM signal LEDs in a garage with all the lights on and it just looks like a bar of bright amber light (side markers converted to side repeaters in this pic with VLEDS high visibility amber bulbs):
