Well, it would really depend on the task at hand and your prior experience. I think LV is really great at acquiring, analysing and displaying data really quickly. You don't need to be a programmer to start using LV and create a good looking UI. VB.NET requires some programming and some OOP experience to work with. Another important factor to consider is what kind of programming experience do you currently have. A C/C++ (or other text based languages )user will be able to pick up VB.NET fairly fast, but might have a little trouble with LV because of the different concepts of graphical programming. LabVIEW will have a learning curve there.
The .NET framework does have alot of support for interfacing with databases (since that was one of the key elements Microsoft was considering during its design), but I don't have any benchmarks for doing db access b/w LV and VB.NET. I believe eventaully the decision would boil down to using the tools that you are most familiar with to get the task done and what kind of codebase do you have in your company.
If you already have a C/C++ based background, then you might find developing an application using VB.NET (or C#) faster than trying to figure out how to use LV. But if you don't have programming experience, then you will probably find graphical programming to be more intuitive.
Hope this helps
Bilal Durrani
NI