I've been doing some interoperability testing between webMethods, .Net, Eclipse with its new web tools, and IBM's WebSphere. There are some nuisances with each product that affect how they work with other web services. As much as it pains me, .Net is by far the least painful to work with.
I do have to give some props to the Eclipse folks however. Their open source product is pretty robust as everyone knows but what is more impressive is their support. I had a few issues and even stumbled upon a bug. The responsiveness of folks on the Eclipse side that helped me out was pretty amazing. I pretty much got immediate feedback that was dead on correct.