I have had problems with this as I am about to upgrade from Samsung Galaxy Ace to iPhone 4s. Eventually I emailed my phone contacts to myself from my Galaxy Ace (go into contacts on your device / then 'import - export' / then 'send name card via' / then 'select all' / then tap 'send' / then tap 'email' option / then email to yourself.
You will then receive an email with your samsung contacts all saved in the CVS format as an attachment, which will import straight into your contacts on your Mac, iPad or iPhone. Works in 5 minutes and seamlessly!