Ivan,
this is a difficult topic. For myself I only can talk about ARIS since I used it for some years. When you start comparing different tools you have to keep in mind that they support different methodologies. ARIS for example has its own methodology which is focused on business modelling. And (from my point of view) the methodology is excellent. The toolset itself is a 100% focused on that methodology. The major flaw is obvioulsy the price you pay. If you're doing business modelling in a big company, it pays if you spend the money for that tool. But for small to medium application it is quite sufficent to simply know the methodology and using a drawing tool (Visio can be customizes easily, but Powerpoint is also okay (limited!)).
Now EA: This is a UML "drawing" tool. It supports nearly all aspects of UML 2.0 plus a lot of additional things like project management, requirement management and so on. But basically it is focused on creating UML models. The problem with UML is, that by now there is no real standard for Business Modelling. BPMN is on its way (and there is support in the new 6.0 release of EA which I haven't tested). Ericsson-Penker offers an UML-based methodology for business description, but it can hardly be used for business modelling.
You should also search threads in this forum which talk about EP and business modelling - there have been a lot of discussions.
