The Philips Corepro LEDs on the edge in a dark shade of yellow, which I did not find that great. The light color of the center was okay and can certainly compete with normal halogen lamps. Because of these properties may be used for effective illumination of pictures or the like they might.
I had tried the MR16 LEDs of MAILUX that did not have the yellow border and subjectively also appeared a bit brighter - sideways or backwards it was here but also dark.
From other often-reported flickering lights or buzzing transformers I can not confirm. Have both lamp types both in a 5flamigen Paulmann rail system as well as in a 4flamigen NoName system (nearly 14 years old) tried (each all lamps with LEDs fitted).
Since both producers could not convince me, all LEDs declined. I'll probably have to wait a while until the MR16 versions find an equivalent replacement.