There are several differences, and the choice of system depends on your particular needs.
Our portable workstations, such as the Radius series, are designed to be as small and light as possible, while still offering high-end workstation and server performance. They feature a durable external chassis mounted on top of a lightweight aluminum frame, that while not expressly rugged, holds up very well to the rigors of field use such as broadcast, telco environments, and even some harsh conditions in military settings. Many customer find that this combination of small size and durable design is ideal, and don't need anything more rugged (and by association, larger and heavier). Also, additional clip-on displays are available with our portable workstations.
Our rugged portable systems, called the Vigor series, take the same internal components as our standard portable workstations and mounts them within an internal chassis, which in turn is mounted on rubber bumpers within a rugged external frame (there is no metal-to-metal contact between the inner and ourter chassis). This design provides improved ruggedness with mil-anodized paint and rubber corner bumpers for more long-term durability in harsh conditions and better resistance to shock and vibration. As such, Vigor systems are larger and heavier, but much more durable than our standard portable worksations. Vigor systems also offer up to two (2) "swing-out" HD monitors, in addition to the integrated display, allowing for a triple-display workstation configuration on the go.
If you need the smallest, lightest mobile workstation available and don't expect your system to be subjected to extreme environments or handling, our portable workstations are your best choice. But if you need the most durable system possible because of your typical usage environment, then our rugged portables may be better for you.