I am buyiing a Sansung S4 phone - do you have details of a good way of transferiing my contacts across? I want all the contacts to come across!
Mark welcome to Android Central. To me the most reliable method of transferring contacts is by making a vcard. Since I don't have an HTC one I cant be specific on how to do it on that device but on a Samsung device you would open contacts>select menu button>select import/export>select export to USB storage. You could then take that file from your phone drag it to your computer and then drag it onto your new device and to the same process as above but select import from storage.
or on your HTC one you can go to settings>accounts>google accounts> sync contacts. Then on do the same on your Samsung device and this should transfer all contacts aswell.
You can check your google contacts from your google account online if you choose to make sure all contacts are there.