Why do I need Unwrella?
Because time is money, and we all know how long it takes to properly unwrap dozens or sometimes even hundreds of objects in a scene. Now imagine that you can select all of them, press Apply Unwrella and they get automatically unwrapped with optimally calculated UV maps, ready for your production.
Because you are tired of fighting with the seams in your textures and normal maps to prevent them from emerging in realtime 3D engines, where they would decimate the quality of your models. Those seams occur mostly because the classic way of manual unwrapping and pelting can never generate exact pixel mappings on the chunk borders (their sizes and orientations usually differ) and will therefore generate ugly and visible seams on the connection edges, since the pixels from one chunk are mismatching with the ones from its adjacent chunks.
Because you dont need to bother about the arrangement of the unwrapped chunks: Unwrella does this automatically. Unwrella distributes them in realtime to ensure optimal utilization of the available UV surface.
Because you will get much less chunks than you would by using other automated UV unwrappers (i.e. the 3D Studio MAX built-in Flatten UV). This offers a reduced number of seams and minimal wasted texture space while still providing the best possible pixel ratio.