<p>Ok, I've seen a few posts that <em>mention</em> a few other posts about not using SP wikis because they suck.</p>

<p>Since we are looking at doing our wiki <em>in</em> SP, I need to know why we shouldn't do it for a group of 6 automation-developers to document the steps in various automated processes and the changes that have to be made from time to time.</p>

The default wiki included with Sharepoint doesn't support common wiki features well at all.  There is no way to edit a single section of a page, and no way to link directly to a particular section on another page.  The backend is in HTML so you lose the ability to edit in plaintext using simple syntax.  The diff feature can't span multiple versions.  Poor cross browser support of WYSIWYG editing.  No way to auto-insert a table of contents...
There are, however, other wiki add-ins for Sharepoint which I can't categorically dismiss, for instance
Confluence
makes an
add-in for Sharepoint
.  I haven't evaluated this software myself, and Confluence is somewhat expensive ($1,200 for 25 user license) although if you are already on Sharepoint I sense large corporate coffers :P. There also appear to be some free add-ins like
CKS Enhanced Wiki
but that appears to have a lot of the same problems mentioned above.