To paraphrase my wife who as some of you know is a CPA with a Masters in Tax and a Diamond QuickBooks Pro Advisor:
Quicken is for personal usage.
Quicken Home & Business is for personal usage or for no ore than a sole proprietor that files a Schedule C with their 1040 tax return.
QuickBooks is for a business that needs more reports than a Schedule C or needs to file other forms for tax purposes.
One of the main reports that Quicken Home & Business does not offer (unless the last release now includes it) is the Balance Sheet. If you plan on applying for a business loan let alone wanting to see important information such as company assets (especially if you're claiming depreciation on it), liabilities and owner's equity.
Personally, I'll say that if you're a business then use business software. That means that instead of trying to do everything yourself(which I'm all for when appropriate), know when you need to bring in others that have the skill sets you don't. Despite the marketing and advertising campaigns, no business and/or tax software will allow you to take full advantage of it unless it is setup properly and you understand certain concept/principals with the tax code. That generally means you'll end up working with a bookkeeper or accountant, and they will recommend that you use a business accounting software as it is easier for them to use the data, versus having to rekey or figure it out.
