KitViewer lets you look into Metakit datafiles if you're on Windows. You simply drag a Metakit datafile over it to launch it:
The left pane lets you navigate to a view, the right pane lets you select a row, after which you descend down into a subview in that row by clicking in the proper entry on the left again, and so on.
KitViewer is blazingly fast for datafiles of any size. It was built with Borland's C++ Builder, which has an amazing data aware grid widget, er... control. As a result, only the visible items are drawn, and due to the way Metakit works, this means that just a few data items are read off the disk - regardless of how many rows are present. Another reason for the speed, is that KitViewer takes the lazy way out and does not display binary data (only the size of B properties is shown).
KitViewer by Brian Kelley serves the same purpose as this utility, but is a completely different app, based on wxWindows and Python (and hence portable).