Step vans, good or bad?

My van is getting old, I am looking in to a new one. Just saw a step van for sale, always thought it would be cool to use one for carpet cleaning. Would look in to  a smaller one, Good ,Bad? Thoughts?
here are some of the positive and negatives
Postive
1 lots of room, you can stand in them
2 aluminum body- no rust
3 Plenty of advertising space on side back front
4 great price point- $5-10 thou for a good one.
5 diesel options, could hook my El Diablo hetar supply right to main fuel tank.
6 Diesel options- loong lasting engines- up to 500,000 miles
7 Fed ex has hundreds used for sale at all times that were well maintained.

Negs
1. large body vehicle not as maneuverable, difficult to position for work
2 heavier vehicle- bad gas milage?
3 dual wheel rear on most may cost more in tolls? restrict movement on Highways?
4 May not fit in my garage for winter- I do have extra high doors, not sure about this.

Please add to this list, I know I am missing some obvious points, Thanks!

Not a fan of the look....I do like the box truck though....I was going to do that but price scared me.

I used work on a customer's machine that is installed in an old Lay's dilivery van. All aluminum body he said fuel economy wasn't to bad. He has his unit out the back works for him, but the only drawback is access to the space between the seats and back of the unit. Everything fans ,Rx20 have to go through the cage up front and around the seats. But he likes it, he has two of them.