Diploma RN have 3 years of school in a hospital based school. Classes are 11 months out of the year. Lots of clinical. In my case I had 8 hours of clinical M-F and then attended classes in the evening.
ADN have 2 years, college based. Usually summers off (not always). Clinical experience is usually 2 mornings a week.
BSN is 4 years, college based. First two years are usually liberal arts (English, Literature, etc.) Last two years are nursing theory and clinicals.
Now, we all take the same board exams and can do the same things. A lot of hospitals don't differ in salary. Some give token differences, usually anywhere from $.25 to $1.00 more an hour. Difference such as a BSN come into play for management jobs, and entry level for certain certifications. However, I'm a hosptial based diploms grad who made nationals on state boards (back when we got real grades, rather than pass or fail. Nationals showed you fell into the upper 10% of those tested in the US) and I'm certified in IC, WITHOUT a BSN. In fact, in my state, Licenced Practical Nurses are allowed to do almost everything a registered nurse can do but write MD orders and give IV push drugs!!! So, goes to show you, we're really all the same, JUST NURSES.