Inspiron and Vostro are the two main lines that Dell has in their 7560 series. The main difference in them is the market they are attempting to serve with them. While the Vostro is geared to service the needs of small businesses at an affordable price, the Inspiron is more for personal users.
Inspiron has more color choices, less software pre-installed, and costs a little more. Vostro is ideal for those who need to do certain things online for their business but don't necessarily want all the frills that come with a pricetag. There is more support available for the higher price Inspiron.
All in all, both brands are great. They are made by Dell and Dell has a good reputation. They are a company who likes to deliver what their customers are looking for whether that is a personal computer for home use or a business computer that economically fits their budget and needs.