I've been using them for years and have tested several prototypes of new ones. Here is a site that has everything you've ever wanted to know about them.
http://www.e-cigarette-forum.com/forum/
Ask your mom to read that site. It's full of testimonials and it is like a support group. There is quite a bit written about health and benefits. At the bottom of the site main page is a very long list of companies/suppliers.
They have come a long way since the awful first ecigs sold at the mall just a few years ago. My favorite is the Janty JETS Tank system. They had a distributor in Ft. Worth who then moved to Benbrook, but has now relocated to, I think, New York now.