We have manual. Must say I don't adjust the seatbelt much. Just undo it and do it up again! Only if they have extra bulky clothes on or something, or as they grow it needs adjusting now & then.

I have heard that the retractable is noisy and can wake the baby.. but having said that.. not sure when you would use it when bub is asleep anyway.

But yeah, manual has been good for us