Moviestorm has its own cutting room where you can cut and splice and even add filters, but there are reasons why you might need another tool as a complement.
The first of these is because it runs on Java and, regardless of how powerful your machine is, it tends to slow down the more you throw at it.  So often you need to restart Moviestorm, or sometimes the computer so that performance levels return to normal.  It is therefore good practice to separate scenes and put them together later.
Another reason to call in help from an external tool is that sometimes you need a little more control.  You may want to do pan and zoom effects, transitions, chroma keying and add fancy motion titles or special effects that aren’t available in Moviestorm.
A good NLE will allow you to apply effects using keyframing which means you can vary the intensity or parameters of the effect at different points in your clip.  Sony Vegas, as far as I can gather allows this on every single effect, but unfortunately this is not true of Pinnacle Studio.
Another must have feature of an NLE is multitrack.  There’s nothing worse than having a very limited number of tracks available, and being able to separate dialogue, music and sound effects enables them to be mixed at different levels, as well as having separate volume and
panning envelopes.
From my limited personal experience for a budget of roughly 100€ my tool of choice is Vegas, especially since the premium version contains a suite of tools for audio editing, DVD and soundtrack creation.  Pinnacle is my second choice in that price range because the studio version contains some Red Giant plugins, most notably Magic Bullet looks, which are a superb addition to a toolset.