We have tried three different vacs including a Eureka Whirlwind and a Shark (don't remember the model) - I don't remember what the other one was. None of them worked very well in our opinion.
A few years ago I took the Eureka into a vacuum sales and repair shop and told him I wanted something a lot better and still small since it was for a motor home. He tested the suction and the airflow on the Eureka (said the airflow is more important than the suction) and came up with a Super Fastvac 500 Vacuum made by Schneider Industries in California. It has 85 inches of water lift and 115 cubic feet of airflow. That was over twice what the Eureka had and over three times what the Shark had. It's pricey - list is $170 (I paid about $130) but it does a heck of a job. I also bought a vacuum powered carpet brush head that cost another $38 and unlike the one that came with the Shark, it is hard to slow down.
It's small: Weight = 4.5 pounds, Dimensions =7”x12.5”x4.5” but powerful and comes with the usual attachments plus attachments for cleaning computer keyboards and the like. Those work great on the motor home dash.
Vacuum shops carry them but I haven't seen them at the mass merchandisers like Target or Walmart. I have seen it at Amazon and other places for as little as $80.
The web site is
HERE if you are interested.