Hi Ken,
I ordered the Ninja with a 2 inch vac port. The short exhaust hose is just to keep the vacuum exhaust noise down. It would benefit from a longer hose but by the time I have lugged the portable gear up to a 4th flr apartment in London I am not looking for extra things to take in.
I like this set up because it is quieter than the Scorpion so I can sit it on a marble/stone entrance hall and not be embarrassed by the noise level. I can also run up to 100 foot of 2 inch hose and still get acceptable performance. I find the Ninja is more solid and much better made and I like the internal heat exchanger. It is quite flexible too because it performs well without the 3rd vac over 25 foot for small jobs. On the downside it is heavier by a few pounds which I accept given the more rigid construction.
If I were running from a van I would still probably choose the Scorpion because noise would not be an issue, the machines is under less stress because it is not being bumped around and I could sit a heat exchanger in the property.
As usual in this this business its horses for courses.
Nigel