Id prefer not to have them.
With both my kids I had to have earlier scans than I'd have liked - DS1 @ 11 weeks for threatened miscarriage, DS2 - dating scan @ 6 weeks and a scan at 15 weeks becuase the OB registrar who did my hospital bookng in check couldnt find the heartbeat with a doppler.

If I was going o ahve any more children I think Id opt to only have the morph scan.