Everyone business, whether small, medium, or enterprises at one time have to deal with the decision making process of adapting the next new technology.  It can be as simple as, should we go with dsl, t1, or cable internet, or as complex as, what should our next phone system platform be, digital, analog or VOIP Phone System.  Regardless of what the decsion is, there is always this one thing about technology!  There is always a Trade Off! 

You want an cheaper phone system - The chances are, you will loose features and benefits of a higher end system.

You want to get the system install fast and not waste too much of existing employees times - This will be great for short term as far as productivity is concern.  When I say short, I'm talking hours or days.  The reality of this is that, it is not recommended.  You will have far too many communication problems.  Employee will not know how to check voicemail and you will loose business.  Employee will not record their names or greeting in the voicemail boxes, which will cause some potential clients not to leave voice messages, and possible loose messages.  Adapting technology such as phone system, voicemail, auto attendant does indeed help with productivity, however, it still does require human intervention.  The more you are willing to learn about the system, the more you will get out of it.  The more you can help streamline your business process.

You want to go VOIP - VOIP (Voice Over Internet Protocol) is now the BUZZ in Telecom Industry.  Is there a benefit to a pure VOIP Phone System?  Yes there is!  There are also trade off!  VOIP can have many benefits.  Digital phone system also has it's benefits.
Here are a few benefits of VOIP - It's much easier to intergrate your phone system with your computer system via Tapi (Telephony Application Programming Interface) vs. Digital Phone System.  You ask, what is Tapi?  Tapi is a Microsoft Windows API, which provides helps intergrate computer application software to your phone system.  A good example would be Allworx Call Assistance Software.  With this software, you can now record a conversation to your PC in a .wav format simliar to music or audio files.  You then, can burn it to a cd or dvd or even email out the conversations.  Is there a trade off to VOIP?  Of course there is!  Here's one that we have found our through many installs.  VOIP cannot possibly be as stable as one any analog phone line or the old traditional Digital Phone System.  That's just something we learn from our experience.  Do we still use VOIP?  Sure, we do.  Because of the flexibility, VOIP is still worth the hassle of going through the new learning curve.  Image if we never accepted cell phone back in the days because the quality is not as great as a land line phone.  Where would we be today?  We have accepted cell phone, the goods and the bad:  Drop calls, poor quality at certain locations, etc.  Is there any reasons why VOIP cannot be accepted by all business?

To keep this short, I will just make a list of pros and cons of digital vs voip phone system:

VOIP Pros:  Lots of features, very flexible (you can work from anywhere), very easy to intergrate with computer system or software (outlook, call assistance, iphone, etc), Voip phone can help you save on cable cost 1 data cable vs 1 voice and 1 data cable per stations.
VOIP Cons:  Not as solid as digital phone system or 1 analog phone, however it is still pretty reliable.
Digital Phone System Pros:  In most case, much more sturdy and stable then VOIP Phones. 
Digital Cons:  Total cost of ownership is typically higher,  not as flexible.