Act! is a specific software application by Symantec used for everything from tracking addresses, to doing msss mailings and tracking sales and services calls. It has received very good reviews and is useful in a wide variety of industries. It has been around for a long time so although like all software it has problems, it is considered stable. i believe other vendors make and sell or give away add-on products to do specialized tasks..
Acess is a database software but you have set up your own databases, reports, queries, wizards.
So it depends on what your client wants to do. If it is something close to what Act! does it may be better to go with that, otherwise to use Access is re-inventing the wheel. However, if she wants to do something highly specialized or already has Access and cannot afford Act! or wants to use this project to learn Access, etc. then Access could be the best solution.