Lately I've been taking a look at the various viewers, as we have an R&D effort focusing on 3D terrain in the ERDAS photogrammetry group. It is exciting technology to work on and we're very much looking forward to getting it out our of the lab and into our commercial software later this year.
After giving the FugroViewer a whirl it became immediately clear what the competitive advantage is: it is blazing fast in terms of the point rendering, refresh, and tinning. I was working with LAS datasets between two and twelve million points and both the load time and performance (on my laptop) were great.
Here's what a LAS file looks like loaded in FugroViewer. The initial view when you load a file is from a top-down perspective.
The user interface is fairly intuitive, and there are options for viewing the file in 3D, drawing/visualizing a user-defined profile, and numerous options for display (e.g. point coloring, TIN display, contour display, etc.). When you press the 3D button a new display panel opens on the right and a navigable 3D view is rendered, displayed below.
Here I have drawn a profile in another scene: you can see the profile overview in the left panel and and the profile view on the top right display. In this case the profile starts on the bank of a river and moves up a hill, with a church on the right hand side (which can be seen clearly if you click on the image to take a look at the larger view).
The software also displays file information about the LAS file - point count, points by return, LAS version, and so forth.
Overall I'd recommend giving it a try out if you're a regular using of LIDAR data, the performance is excellent and you can't beat the price.