As expected Microsoft obviously settles to run in place regarding the Mac:
http://arstechnica.com/apple/news/2011/07/improved-office-compatibility-coming-to-lion-but-not-for-a-few-months.ars
For what it's worth since they have no intention of supporting Hebrew on the Mac and pass the buck to Apple, you might think twice about investing in Office unless you absolutely have to use it.
And I have absolutely no intention of upgrading to Lion in the near future. I dislike early adopting a new OS. But one thing I must do is upgrade my Mini to Snow Leopard.
Support for Hebrew and Syriac is actually much improved in Lion (not perfect, but better…).
As I am no Hebrew expert, I can't tell you whether it might be "good enough" for your purposes, but it's at least worth looking into.
If so then maybe MS will be completely without excuse. Mellel is proof that MS hasn't put forth the effort in the past. Anyone tried Hebrew with MS Word and Lion yet? If the Lion OS supports it with MS Word, I'll happily step off my soapbox. I still use an older version of Office in Snow Leopard for business and personal use, but use Mellel most of the time for writing.
Support for Hebrew and Syriac is actually much improved in Lion (not perfect, but better…). As I am no Hebrew expert, I can't tell you whether it might be "good enough" for your purposes, but it's at least worth looking into.
I am using the Office '11 for Mac trial version and I just copied and pasted Hebrew text from Genesis 26:5 and this is the first time I have seen MS Office NOT switch the words around completely. In '08, every word has the first and last letters switched completely around every time you copy and paste. In Office '11, it stayed the same. All I had to do was change the paragraph alignment. The vowels, however, do not line up perfectly under the letters. Most of the vowel markings underneath the consonants are shifted slightly to the left. For Hebrew (and Syriac in the future, after I learn it that is), I use either Mellel or Nisus Writer Pro. The vowels line up perfectly (using SBL Hebrew font) underneath the consonants. MS Word still does not recognize the SBL fonts, though, so even though it retains the SBL font, if there is an error of some sort, the font changes, even though it still says SBL Hebrew or SBL Greek. So, either Mellel or Nisus Writer Pro is better for Hebrew, etc. (since they DO recognize and allow you to use SBL fonts). I AM finding that I like Office '11 better than '08. They have improved many things, and it just feels easier to use. So for anything else, Office '11 could actually be better and easier to use than Office '08. (Oh and I forgot to mention that I am running OS X Lion 10.7).
I agree with Michael that Mellel is a great solution. It got me through my OT classes in seminary. However, I'm an even bigger fan of Scrivener. If you write sermons or large projects regularly, it is a great solution. It does a very good job of handling Hebrew as well. You can get a free trial from their website, and it's also available on the App store. Here's their site. http://www.literatureandlatte.com/scrivener.php