Vantaggi
An education in the psychology of a short sales cycle. You get to see a lot local businesses and meet a lot of owners. High activity leads to sales. You can get a new territory and still go back to your old territory and stay on top of the prospects who's contracts will expire. You learn to overcome objections and develop a thick skin. Good entry level position to learn the trade of sales. Firsthand experience witnessing the psychology of closing the sale. Exposes you to a lot of businesses that you would otherwise simply drive by and not notice. Growth opportunity for those willing to put in the time and effort. Good support from management - you just have to ask for it. Initiate the communication with management and you will do fine.
Svantaggi
You get a lot of "no's" or people just putting you off - it's sales. It is difficult to move up in pay tiers each month. Most sales don't pay very much, so commissions tend to be small. When you do get a "big" sale, it becomes the temptation to only focus on large companies - because that's where the money is. A lot of suppliers out there and most aren't very ethical and thus you walk in the door with this very stain and encounter immediate distrust. The psychology applies to both you as a salesperson and the prospect.