I'll try MS Accounting Professional as soon as I get a chance. The free (Express version) definitely won't work for me since I work with a lot of inventory.
I can't tell you about the 2008 version yet because I have not tried it, but I'm really looking forward to trying it. (downloading now as I type)
I can tell you about the 2007 version though (the PRO version anyways, I don't care for the Express one)
I really liked it and would've definitely switched from QuickBooks, except I could not successfully migrate all my data and it was kind of slow. If this has been fixed in the 2008 I'll dump QuickBooks.
I've been using QB since 2003, currently I use QB 2006 Premier. I like QB because it's very easy to use and flexible. However, it lacks multi-currency support and has limits for the number of inventory items, customers and other lists you can have. This is something I really need, I've had to set up several company files to overcome these limits, but it's a pain to manage.
We've been asking Intuit for years to add multi-currency support for the US version, but they just don't listen or don't care.
MS Office Accounting PRO doesn't have this kind of limits and it has support for multi-currency!
I've tried a few other accounting programs, including PeachTree Quantum. None is as easy or flexible to use as QuickBooks, except MSOA.
If I'm able to successfully migrate all my data and it doesn't run as slow as I remember, I'll definitely make the switch.