The authors' expertise in the subject is clear. These guys have been doing this for a long time, and know it inside and out (or at least as well as can be expected at the time of writing). It reads really well, and their added insight is great.My major issue with the book is that it really should have been titled "ADO.NET Examples and Best Practices for C# Programmers Who Are Already Experts in ADO Using SQL"
Basically if you aren't interested in the differences between ADO and ADO.NET, you'll find yourself skipping over quite a few sections. I got the feeling that I was reading stuff like this a lot - "This isn't any different than ADOc (how he refers to COM based ADO) so we'll just skip over that and get to what's different." Or - "Here is a comparison of how these ADO properties map to their ADO.NET equivalents."
In addition, if you are looking for info specific to anything other than SQL server, you may be disappointed. The book just makes minor mention of OLEDB.
If these issues aren't a concern for you, consider this a 5 star rating.