After Verizon, then Apple lost my extensive contact lists, I searched feverishly for an app at would give me backup on my iPad and at a remote location. Phone Copy made it possible for me to combine a few lists containing duplicates and near duplicates, and let me go back in time to find things that were deleted by accident. When I have issues or suggestions, I send an email to this app, and I feel that my concerns are being addressed.
I use the internal backup function for ContactsXL on iPad versions 1, 2, 3, 4, and two iPhone 5's, and I use the this app app to synchronize everyone. I've been so grateful, I became a paying subscriber! Since I'm on a small limited income, that is a big deal! Thanks PC!