The truth of the matter is that there isn't much that TADS can do but Inform can't or vice versa, and Hugo is just about as good as the top two; it is just that some things require a bit more work than others on some systems. ALAN is also not a bad choice; it is not as powerful as the other three but some have found it easier to use.
It has been commented that the most difficult thing to learn in any IF language is not the syntax of the language but its world model. Knowing the peculiarities of the language is easy compared to understanding the interactions between the objects of your game world. If you can write IF at all, then you can certainly master any of the major languages. Many have.
If you are still concerned about the syntax of the various languages, you can check out Roger Firth's "Cloak of Darkness" at <http://homepages.tesco.net/~roger.firth/cloak/>. This project has the source code for a simple game in many of the main IF languages, complete with comments on how it works. You can look at it to see a sample of how each language works.