Awful, really awful.

I avoid it as much as I can.
Slow. un-sexy.
what's really bugging me is those services that required Acrobat reader and nothing but it.

I really hate Adobe Reader. It looks like starting a complete Final Cut Studio when opening an PDF with Adobe Reader. It is simple horrible! I Love Preview I really love it. Also I did find a solution for missing fonts which is to dowload them or grab from my windows installation (Parallels, sorry I HAVE TO use it in my office) and there is a lot of instructions how to make them available for every App.
So far, I love my Mac!

Adobe Reader 8.x squases fonts of about 90% of the PDFs I tested, no matter whether they were created with Distiller, Quartz or OpenOffice. Also, font antialiasing seems borked for most fonts. The same applies to the Windows installations I tried out, so it seems to be an issue with the font render engine in Adobe Reader in general.

I definitely hope those issues will be addressed in the next version of Adobe Reader. Most of my contacts use it, and I don’t feel like explaining to them that the product sheet I just sent them doesn’t look shitty, it’s Adobe Reader.

Adobe Reader 7.x rendered those PDFs fine, I should mention.

I would like to use Apple preview to everything, but it fails to render some fonts correctly and hasn't got fullscreen mode. i have never liked acrobat reader on pc, but this version is ok, but nothing more. I really miss the bookmarks from preview

But why oh why
is the download and installation process
for Adobe always so...
...fill in the blank yourselves.

Amazingly enough, version 8 no longer sucks. Version 7 was awful, but v8 looks much more Mac-like and is quite a bit faster. Much as I love Preview, it has trouble searching scanned + OCR documents, and also doesn't seem to handle PDFs with built-in forms. Also, the Adobe Reader browser plugin has search built-in, which Apple's standard plugin doesn't. So there's definitely place for both Preview and Reader.

The biggest problem with Reader is installation. Rather than simply downloading the application, you have to download an installer, which then installs a "download manager", which then downloads the real installer, which finally installs Reader. WTF!?

v8 is much quicker than v7.

This is basically an echo of everyone else's opinions:
It's big, VERY slow, and not worth the hard drive space, except perhaps for the exceedingly rare time(s) when Preview doesn't work perfectly.
I should point out that, after using Preview to open a few hundred PDFs, I've never had it render incorrectly. Not to say it can't happen, but it's very rare.

There is pretty much no reason to get this app if you own a mac. Preview comes free and it has enough features for 99% of people.