I used Preview for viewing pdf's until I ran across files that contained math equations and symbols were missing in preview. I downloaded acrobat reader and I'm happy with it. I use QuickLook as my default, Preview as my secondary reader and Acrobat only when formatting is messed up in the first two.
I am a daily switcher to OS X. When I'm at work and want to open a document, I must sit through a 45-180 second launch agony to get Word 2007 or some other bloated pig of an application loaded simply to view a document. At home I hit the eyeball in finder (add quicklook to finder toolbar and it shows as an eyeball icon). quicklook knows how to open 90% of the files I use and there is no long wait for a full app to load. BTW, iWork 09 and Openoffice.org take just about as long to load on OSX as M$ office takes on Windows.
Somebody really needs to take a look at office suite bloat and offer us something that loads as quickly as textedit that does 75% of what Pages does. BTW, for editing rtf documents, Textedit does a great job and is fast to load. If you're working on files on both platforms, rtf is a better file format to use than doc or docx which require bloatware to edit.
I should mention that Acrobat on OSX is better than Acrobat on Windows. On windows, when I open those huge pdf files, Acrobat bogs down so I use the freeware SumatraPDF and it opens them quickly.
I find this happens a lot. I may not like a certain piece of software on Windows but it works better or faster on OSX. This is especially true for Print drivers. I tossed out most of our HP printers but I keep a PSC2500 all-in-one around. On windows, it needs 700 megabytes of "microsoft dot net" bullcrap and HP support recommends installing and uninstalling the driver over and over again hoping to "get lucky". I spent an hour on the phone with them and in the end they offered to sell me a new printer at a discount rather than keep trying to make their driver work on Windows. The same printer driver on OS X is only 30 meg. I own Brother printers because they ship with OS X drivers that are either already included in OS X or are small downloads.
Since you say you are new to OS X, I'll pass along a few things I've learned that might be of benefit. On Windows, when you place something on the clipboard, it is in "windows metafile" format. On OS X, it is in pdf format. Yes, the native meta file format for OS X is pdf. That's why when you print a document, you don't need to print to a special "fake printer" to get pdf. PDF output is an option on every print dialog. Usually in the lower right there is a pulldown that says either PDF or Save As PDF. I would steer clear of 3rd party applications that claim to "help" with pdfs. They aren't offering any real help. PDF format is central to OS X and all the help you really need is already present in the OS. For instance, when I use an equation editor on OS X, it wants to save the equation as a pdf file. This threw me off at first, but then I tried pasting one into a document and found out it was just like pasting in a windows metafile on Windows. Of course, for bitmap graphics you can always work with jpg format, but for line drawings it is better to stick with pdf. This is another thing that threw me off. I went looking for insert->picture->from file and didn't find it. On OS X you can either paste it in or simply drag it in. This works from a browser as well. You can grab an image you like on a web page and drag it directly into pages or open office writer.
