Hi! I go to Purdue, majoring in health science. I can tell you Purdue is a great school with many, many resources (so doing well in your classes should not be difficult provided you have the drive to do so).
That being said, the above poster is correct in saying that Purdue is BIG. It has been difficult for me to establish close relationships with my professors. It's taken me until junior year to take a science lecture with less than 150 people in the class. However, research opportunities are very ample at Purdue and if you get into a professor's lab, you will undoubtedly have a great source for an excellent LOR.
I would also add that Purdue is generally held in higher regard than Valpo, but the difference isn't very significant.
Let me know if you have any other questions about Purdue.