When using 'virtual' credit card numbers, using cut/paste from my banks' UIs to Ting's UI doesn't work terribly well for the card number. The reason is that although there are 16 digits in the number, the 'cut' from the banks' UIs includes spaces between the four blocks of digits (and, if not careful, some leading and/or trailing spaces). The Ting input field causes the last three digits to be truncated so one has to delete all the spaces manually and then type in the last three digits (although I suppose I could cut just the three digits from the bank's UI -- but that's hardly worth the trouble).
This process is slightly inconvenient and error prone. It would be more convenient if the number of characters allowed was expanded and then embedded, tailing, and leading spaces were deleted before validation/storage.
I really appreciate the sites that get this "right" (which appears to be about 1/3 of the ones I use) - it's a small thing, but a bit of "customer oriented polish".