I have been thoroughly impressed with how simple Box.net is to use. If you want to quickly share files, Box.net makes it very easy to do so. Beyond just sharing, Box.net is also extensively feature rich (for example it enables you to embed a list of files to share/access on your web site) with the features being easily accessible.
Microsoft Sharepoint is a very powerful application, but from what I understand it's not easy to deploy and can be costly when you combine the license and installation/customization fees. Large corporations use it as they have the budgets to install it, need the robust features it indeed does have, and need the integration with Microsoft Office.
I was looking at a video from Box.net,  which was all about how sharing should be simple and got to thinking that SIMPLICITY and EASY OF USE should be two very important parts of buying any technology.
Price is VERY important. But price should not be the most important consideration.
As you look to buy technology products for the growth of your business keep these things in mind:
Price: You need to buy within your budget but not pay less only to have to pay more in training, replacing the technology, or buying other technology to make up for the deficiency of the "cheap" technology, later on.
Ease of use: As smaller businesses you DO NOT have the luxury of spending hours and days getting technology to work or the money to hire someone every time you want to use new technology.
ROI: Ensure that you will get a reasonable return on your investment with EACH AND EVERY technology you buy. If the technology does NOT positively affect your bottom line, you don't need it.
Of course other things are critical, such as getting buy in from employees, testing the technology, ensuring enough training is given and leaving room for growth (e.g., can that $4.99 per month payroll system help you when you reach 78 employees?).
Going back to Box.net, which I have used - the file sharing service is aggressively priced, feature rich and I was overwhelmed with how simple it was to use. Sharepoint is a great tool for larger businesses. But for smaller businesses there are simpler tools, specifically designed for smaller businesses.
Whether you're buying an $800 server, $4.99/month payroll service or something other technology tool, keep these three points in mind.