Frequently we are asked this question. Either one is fine. If you are using a legacy version, however, see the "special considerations for legacy versions" section below.
Most importantly, make sure that you obtain at least the "Professional" version of these operating systems and preferably nothing lower (i.e. for business/networking purposes you want to normally void "Basic" and "Home" versions).
Ideally all PC's would simply come with the so-called "professional" versions.
Because of the touch screen interface and the fact that even with the program menu having returned in Windows 8, corporate users are still commonly choosing Windows 7 over Windows 8, and for most users, that remains a reasonable/safe/efficient choice.
Despite some its awkward tile and other interface issues, Windows 8 does seem to be very solid in terms of reliability and memory handling. A number of our users are using Windows 2012 Server which uses the "Windows 8" interface. Heavy desktop users will still likely prefer Windows 7.
Special considerations for legacy versions:
If you are using a 16-bit legacy version such as Advanced Accounting 5.1 or prior, or software based on TAS Professional 5.1 or prior then you need to be aware that unless you have the 32-bit version of Windows 7 or Windows 8 pre-installed (instead the 64-bit version will likely be pre-installed), you will not be able to run the software without going through extra hoops and may also have networking limitations if you plan to use your legacy version in a multi-user or multi-device (shared resources) environment.
Your system type (32-bit or 64-bit) can be determined by checking your system information properties.
Even if you have a 64-bit system type, it is still possible to run 16-bit legacy program.
Windows 7 Professional and higher: install the the XP mode. See Install and use Windows XP Mode in Windows 7.
Home versions (64-bit Vista, Win 7 or Win 8): One option would be to run the legacy programs under a virtual machine such as http://www.vmware.com/products/player/.
With Windows 8 Pro or higher, the included Hyper-V is available to run via a virtual machine. See http://windows.microsoft.com/en-us/windows-8/hyper-v-run-virtual-machines.
A few more references for legacy users:
64-bit versions of Windows do not support 16-bit components
Windows 8 Program Compatibility Assistant
Normally the best answer for legacy accounting software users is to upgrade their 16-bit version to the latest version of Advanced Accounting, and we will install and convert all of your data (everything moves forward and nothing is lost) for you remotely at no additional cost beyond the cost of the software update.
Addsum web site and general info
Postings here will focus mainly on Advanced Accounting software updates, tips, and related topics. They will also include general comments relating to troubleshooting PC/Windows/network problems and may also include reference to our other software products and projects including any of our various utilities, or to the TAS Premier programming language. We considered setting up separate blogs for different topics so that users/others could subscribe to topics mostly aligned with their interests, but decided that it would be better to keep things simple since some topics cross over into others. We would nonetheless welcome your feedback/input in this regard. Our web site URL is www.addsuminc.com. Call us at 800-648-6258 or 801-277-9240. We also maintain www.advancedaccounting.us so that older Business Tools users in particular have a greater chance to find us.
We highly recommend that accounting software users "follow" this blog via e-mail (enter your address and click on Submit below) or subscribe to a feed (see also below) as a way to keep current on the latest updates and accounting software news and information. You may also want to whitelist this e-mail address: firstname.lastname@example.org.