Which one is better for Data Access Library?

[D]

I am developing a reuseable data access library for Access, MSSQL, MySQL,
Oracle and etc, for some of other projects.

Initially I build up classes for each database, and a client application is
required to create instance before it can establish the connection and
retrieve data from database.

However, I find in a source sample of Microsoft Data Access Application
Block, which has a NonInheritable class with all the methods in Public
Shared. So the client application can just retrieve the data by calling
directly the static class methods.

I start to think that my original approach may not be as good as the sample
by Microsoft, can anyone tell which one is better?

Thanks