Before you buy software check Secunia to see if there are any advisories on that software and how quickly they were fixed:
Also check the true roots of the software maker and other products developed by that same company or a previous company with the same owner.
Check for third party, credible reviews of the software but also, don't believe everything you read. Do your homework and find out what other companies are using the software and who the reviewer is - related to the company? And is the reviewer technical enough to offer true advice on the software?
Make sure that reviews are not just of the features, but also of the underlying security of the product as well. A piece of software may look cool and have nifty features but also have a back door into your trusted environment.