You are not alone in experiencing louder lifters initially when switching to synthetic. Again, I have not had this issue myself, but I do know of one individual who has seven (7!) vehicles with OM60x engines. He strongly advocates the use of synthetics in these engines, but urges owners to be patient, as the true benefits, including noisy lifters, may not become apparent until 20-30kmi following the switch.
'04 ML500 - 53k, Inspiration Edition, Desert Silver
'11 Audi A4 Avant - Brilliant Black
'87 300SDL sold
'99 C280 Sport sold
'85 190E 2.3 sold