I have been writing code with CSLA 3.5 in VB.Net.  I have to say there are some really cool new features.  I love the fact that that the backing fields for properties are a hybrid of fields and smart objects.  Who really liked setting the PropertyHasChanged in every property set.  This is much cooler.  I'm still picking up on the child objects and few other nuances. 

I am working with Oracle so I use DataSets (ugh!) to handle the data.  I have been using some Linq against them and it works great.  I can't wait till there is a Linq to Database.  You have to think that it is going to come along some time.

Since I switched to C# full time, coming back to VB.Net really sucks.  It is entirely to verbose.  C# is just straight to the point and gets the work done quick.