KISS: Use REST always, never SOAP.
I've implemented many Web services using both standards and I can tell you categorically that in hindsight I should have used REST always.
Some time ago, I started to develop programs using tiny, super general, higher-order functions and I began to borrow a little from functional programming. I noticed interesting things about these new programs. They called for special language features that I had until then heard of but never really needed. I'm referring to language features like support for first-class functions, closures, and lexical binding. The programs I produced were smaller and easier to debug than programs written in a traditional procedural style.
The big problem with Perl is that it’s easy to learn, but difficult to learn right. It has a tough learning curve and it can take years to master, even if you already know many other programming languages.
However, I’ve never met a person that uses the advanced features of Perl (closures in an OO context, hash dispatchers, higher-order methods, super general functions, and so on) that didn’t write beautiful, concise, fast, and bug-free code. People that really grok Perl (and there are precious few of those because of the learning curve) don’t bash Perl.