Interesting you should think that. My experience was just the opposite. I was excited to download the try Acrobat 7, but I ended up deleting it within ten minutes cause it drove me crazy.
The interface in the program is still really "laggy" and slow. When you click on the button to do a search, the window should be able to pop right up. but it still seems like it's really slow on those simple functions. But the real reason I still don't like it is because of the speed. When I scrolled down through this one PDF file, it was very delayed in rendering the page. Like I would do a scroll, and where the new part of the next page needed to be rendered would be white for a spit second before appearing. Where in preview, as soon as you scroll down the new content appears. Does anyone else notice this? Or is it just me?
But the real reason I deleted it was because of the new Safari plugin. Now acrobat works inside Safari. So when you click on a pdf file, it open's it in the safari browser window itself instead of downloading it. Then when I clicked on the "save" button, the acrobat plugin froze up my Safari App.
Conclusion: I removed it. I still like preview better. Acrobat still has the markings of sluggish, buggy, "ported" software.