The engines built on it show that it is fairly competent.http://xen.codeplex.com/wikipage?title= ... Title=Homehttp://www.synapsegaming.com/products/sunburn/engine/
For me, XNA looks like a DirectX wrapper in C#. The point is, why restrict yourself to a wrapper, when you can have the real thing with Irrlicht for the same price
The limits of XNA are as follow:
-Windows Platform only
On contrary, XNA has other advantages over Irrlicht, like the fact that it is an API for C# to build games, not only graphics applications, which means that it has full support for controllers, network comunications and sound. And it can use directly FX files, so, multipass shaders are also supported in XNA.
Why i prefer Irrlicht over XNA? i learnt to use it before. And i feel more comfortable with it.