I am one of those people that really doesn't like change that much, with the exception of weight loss and all products sold at Best Buy :-)
I have to say I am still using the previous interface more. The new one is fancier looking and looks great on my wide screen, but I have to get use to it.
One thing that is a massive improvement is that you do not have to click on so many things to read results. For example, my blog results for yesterday- regarding visitors is easy to view:
375 Visits
179 Absolute Unique Visitors
909 Pageviews
2.42 Average Pageviews
00:05:07 Time on Site
47.47% New Visits
I also like the new bar graphs for "Visitors" info which gives you a lot of data quickly and is easy to scan through. I will get use to it I am sure, but right now I guess I have to get over my dislike for change.