SKYPE may well be the most downloaded free software to date.  And it is used by individuals and
corporations globally.   During late Spring 2005 there were some news of network congestion in the
SKYPE network but this has been alleviated to some extent.  Specialized handsets with features
countering VOIP weaknesses are often reported "sold out", a solid indication of continuing success. 
And as it is, a specialized handset with digital compression, echo management and hidden bias-tone
brings out the best in VOIP.  For the private user, SKYPE is a very interesting ad viable option.

Drawbacks for corporations:  This is a completely different picture, unless it has been decided to
support SKYPE on a corporate level, but even in such cases there are issues to contend with. 
Whenever a software product is installed on a corporate workstation, the End User License Agreement
(EULA) should be examined, whether the software in question is free or not (carries hidden extra costs).
In SKYPE's EULA there are a couple of sections that should cause some concern, or, at least be
carefully considered:

The entire Article 2, concerning reliability of service in relation to versions of the software will need
to be appreciated - and it needs to be accepted that SKYPE is not to be counted as an 100% available
product at all times.

In Article 3, this section might be of interest:

In effect you are made responsible for constantly  monitor for changes to terms of use and SKYPE's
practices re privacy and use of information provided, directly or indirectly.

The entire article 4 is reason for recommending a corporate ban of SKYPE:

Here it is made very clear, that SKYPE will use varying levels of bandwidth of your (corporate)
network. If a corporation lets it's employees install and use SKYPE, then it will impact the function
of a corporate network to an unknown degree, but importantly, without the corporation having
any decision power as to WHEN this happens. . .   For network capacity planning this is a
potential disaster - and an unknown hit to the SLAs. In a previous version of the EULA it also
stated words to the effect, that from time to time that any computer in the SKYPE network
might be used as a "super node" (for routing unspecified SKYPE traffic).

This clause is no longer present - either SKYPE does not need this functionality OR it has been decided
to omit any reference to it.  Judging from the many disclaimers, it could be argued that SKYPE does
not need to divulge any references to the architecture of its network.  For the historically interested
the text is here:

But, as stated above, this text no longer appears in the Privacy Statement, in the EULA or Terms of Use
In many other places in the legal documents SKYPE S.A. reserves its rights to modify any part of the
architecture as it sees fit.  This may in fact mean a return to the "supernode" function if needed again
or any other change which may or may not have an impact on corporate network badwidth.