I'm one of "those" people that paid for Eclipse, an open source IDE. I originally bought it because I love and use Eclipse a lot for my work and I wanted commercially available support for the product on which I depend so heavily.
Zend recently released version 6.1 of Studio for Eclipse, with very little (if any) fanfare or announcements (I didn't know about it until I looked at the download site), compared to the release of 6.0.1 which was heralded in their newsletter, all over their website, and everywhere Zend's press team has any influence. I find this ironic, because 6.1 contains huge improvements and more fixes than the upgrade to 6.0.1 did.
Clearly the biggest change is Studio 6.1's move to being based on Eclipse 3.4, the most recent edition of the IDE. This brings with it a whole slew of fixes and improvements on its own, such as a (marginally) improved install/update engine, more efficiency with how the thousands of Eclipse files are handled, some better over-the-shoulder security, icons and more colors now in various interfaces (such as search), and a whole slew of enhancements to SWT, the graphics engine that renders Eclipse.
Anyone who has used Eclipse/PDT knows that there is a lurking bug that manifests seemingly at random during which the PHP builder/parser will get stuck in some sort of infinite loop. This tied up the workspace task queue, which meant that many other functions were useless when this bug reared its ugly head. The only solution was to kill the Eclipse process and restart it, hoping that your workspace didn't require any Notepad surgery to recover. All that is over in the new version of Studio for Eclipse. Let the villagers rejoice!
A minor annoyance I encountered while updating to 6.1 is that it's not actually an update. Instead, I had to download the full 6.1 release and install it separate from 6.0.x. Zend claims this is because 6.1 uses Eclipse 3.4 -- apparently there isn't an easy upgrade path from 3.3 to 3.4 -- oh well. Overall, though, just installing 6.1 was fine as it was able to load up and understand my workspace just fine. The worst part was re-installing my favorite plugins, like QuickRex.
While Zend solved my biggest gripe about Studio for Eclipse (the building PHP problem mentioned above), they've managed to incorporate a new, really annoying issue. If the Code Analyzer marks a part of your code with a warning or error, in some cases the syntax highlighting just stops after that line. The only way I've been able to get the syntax highlighting to return is to disable the specific error that the Code Analyzer was flagging (usually something like using the value of a function that might not return a value -- duh, then NULL is a possible return!) and rebuild the file. The next time I encounter it, I'm reporting it to Zend to see if that commercial support I paid for really works...
All-in-all -- I'm very pleased with Studio 6.1, and at this point, I'll continue to be a Zend customer, and Studio for Eclipse will continue to be my IDE of choice.