It is not true that you can't use Servoy Eclipse distribution to install third party plugin, however some of them might not work, but that's only because the Servoy installation is somewhat improperly configured, see this post for details:
http://forum.servoy.com/viewtopic.php?f=8&t=12389I sincerely hope that these issues will be fixed, so that will allow all of us using Servoy as a regular Eclipse distribution, or maybe make Servoy a real Eclipse plugin, that would be the best!
Just remember that Servoy is based on the Europa version of Eclipse (3.3).
I have installed SVN Subversive, Aquarius ORM Studio, Azzurri Clay and WireframeSketcher and used them inside Servoy Eclipse 4.1.2 (the latter worked on one installation not on another, I can't say why!)
I also use Servoy to write Java plugins and beans: all you have to do is create a Java project and activate the "Java" perspective, it works just as any Eclipse would... It's great to have everything in the same environment and use the powerful perpective switching and customizing features.
But anywya, if you prefer working ouside of Servoy for Java development, you can install another Eclipse on your hard disk and they won't interfere. I regularly use 3 different install of Eclipse on my PC: Servoy, MyEclipse and Talend Open Studio, they all work seamlessly. In the past I used a few more like RadRails and oXygen and never had any problems.