Unfortunately for us (my wife and I), we do not know what we do not know. But, with that said, my wife has commented a couple of times that it can be difficult to see in the viewfinder due to its size and clarity.
We haven't used any different cameras, so we wouldn't know that the view finder is 'small'. However, just KNOWING NOW that there is a camera with enhanced LCD, a larger viewfinder (I felt the view finder was small) and a 100% view in the finder is pretty significant. More external controls is definitely a plus, not to mention the ISO noise reduction (this will be significant for us due to her taking lots of pics of my band on various stages in low lighted clubs).
For the money, the D5000 is exceptional. I just didn't know that my wife would get SO into photography SO fast.
I didn't do a ton of research on the D5000 (although I did some), and admit that Ashton Kutcher sold me with the twisting view finder on the commercial! HAHAHA My wife has only moved the view finder ONCE in a live application out of the nearly 17,000 pictures she has taken in almost 4 months. To us, that isn't a high enough percentage to warrant the movable viewfinder as a must have.
Now that photography is a passion, we are printing LARGE prints, taking classes and FINALLY doing research on products, we realize that a step up in technology may make our lives a bit easier when taking photos. It will not in most cases give us better photos, but the ease of taking pictures be increased.
Sorry for the long winded answer. Thanks for asking. I appreciate your question and time.