Web of science
Scopus is run by Elsevier who are a major publishing house. It includes most of the journals on WoS, not only Elsevier journals, but will include all Elsevier journals and some more that do not have an impact factor. Thus, it tends to include more journals than Web of Science and, as Elsevier are major publishers of health and nursing, is advantageous to some subjects, especially nursing. Your library will have to subscribe to Scopus. Scopus has one feature missing in WoS which is that you can generate an h-index with and without self-citations. WoS allows you to remove self-citations but does not generate and h-index. My experience is that Scopus awards an h-index 2 points higher than WoS when self-citations are included and reduces this by 1 point when self-citations are excluded.
Harzing's Publish or Perish
Harzing’s Publish or Perish (PoP) is available free through public domain down-loadable software that trawls Google for your publications. It is very inclusive, including anything that is available on the Internet and found by Google. Therefore, it includes journals, books, chapters, conference proceedings and reports. At one level it is very easy to use: type in your name and press 'Enter'; however, if you have a very common name then it will find everything by everyone with that name and this can mean checking through hundreds, perhaps thousands, of hits and also checking for duplicates. Clearly, with such inclusivity, PoP tends to be very generous in assessing your citations and h-index. It does provide other measures of citation such as the g-index. In my experience it is unstable, providing vastly different estimates of h-index on different occasions.