Yes, most buyer prefer the end units because you have more natural light coming in. Also you have one less common wall so it can be more private and quiet. I see about a 5% to 8% premium for end units over middle units if the square footage is similar.
The short answer is, it depends! Location within the development, proximity to streets, what is located next to the unit and how much area you own all have a bearing on how it is valued. Since there is no association fee, you would be responsible for maintaining the adjacent area. So you would want to be certain that the configuration benefited you. I agree with all of the other reasons why it enhances the value such as more natural light, larger unit, etc. , but would need to look at the specfic situation in order to give a more conclusive answer.
Best of luck in your search!
Prudential Fox & Roach Realtors