I'm using Netbeans for my day-today java projects, and I really have difficulties when I have to use Eclipse, but I often think that part of it is due to me being new to Eclipse rather than Eclipse itself. However, I also often find that there are real problems with Eclipse, and that my problems are not just coming from my own perception.
But this post is not about GWT, on which I have nothing bad to say, but about Eclipse itself, because GWT is an Eclipse plug-in.
First installing Eclipse itself (I used the last Helios version) take ages, in fact it takes so much time (and often it is freezed during the process) that you often think that there may be a problem. And I'm just talking about the first Eclipse internal configuration after you had unzipped the file containing the Eclipse file structure (what, no proper installer?).
Second installing plug ins is really awkward. You have to know the exact URL of the files to be able to download them (from Eclipse), and you HAVE to do it in Eclipse itself. And the UI to choose them is really poorly designed (it seems that you can't put a load of different URLs and download them all at once, you have to download the:m one by one). As for Microsoft software, it also seems that you have to restart Eclipse a lot of times in the process.
Another problem is that if you have to use Eclipse with it's plug-in on a PC not connected to internet, it's really difficult to do so. Basically you have to download it on the spot (something which is not always possible). Which is really awkward considering that there is no proper installer for the core Eclipse itself.
I also have to mention the fact that Eclipse is generally slow (that is, if you succeeded in the previous steps).
I really don't know how Eclipse can be so successful, where it has so much major shortcomings. I have to say that none of these problems exist in Netbeans: finding and downloading plugin-ins is really simple, you can do this by internet or using local files, installing Netbeans is REALLY shorter, and it's generally much more responsive. You can even copy an entire Netbeans directory with it's plugins, and it's working with really minor changes in the configuration (in fact, only one, the path of the JDK).