The feature to add strongly typed LINQ support to the builders doesn't suppport updating of nested collections.

For example, it's possible to write an update like:

statusCollection.Update(
Query<StatusGroup>.Where(sg => sg.Statuses.Any(s => s.Id == status.Id)),
Update.Set("Statuses.$.UpdateTime", DateTime.Now)
.Set("Statuses.$.Name", "name")
);

It would be nice if it was possible to write something like:

statusCollection.Update(
Query<StatusGroup>.Where(sg => sg.Statuses.Any(s => s.Id == status.Id)),
Update<StatusGroup, Status>.Set(sg => sg.Statuses, s => s.UpdateTime, DateTime.Now)
.Set(sg => sg.Statuses, s => s.Name, "name")
);

Eventually it would be nice to support multi-level nested collections but that might be dependant on https://jira.mongodb.org/browse/SERVER-831