How has having multiple implementations affected Python
<p>Python has 5 implementations listed on their homepage:</p>

<ul>
<li>Python / CPython</li>
<li>IronPython</li>
<li>PyPy</li>
<li>Jython</li>
<li>Stackless Python*</li>
</ul>

<p>When considered against languages such as PHP or even Java that seems like a lot of variety not seen elsewhere. Yes there's different compilers available for C/C++ but for a popular interpreted language this variety seems unique. </p>

<p>It would appear many of the implementations are still on the 2.7.x branch, so I might surmise that this has slowed adoption of the 3.0.x series (along with backwards incompatible changes).</p>

<p>So, how has having multiple implementations affected Python as a language? </p>

<p>[1] <em>Stackless python is a branch, not a different implementation, but you see what I'm going for</em></p>
