Experiences with Flow Router vs Iron Router?

Actually if to simplify, what I have is similar to this:

// logical template, where most of data is handled and passed
<template name="App">
  {{> Layout_app menu=menu articles=articles}}
</template>

// visual template where data is actually showed (can be used by several different logical modules at different times)
// in reality, one Template.dynamic can be nested at least one step deeper in the hierarchy
<template name="Layout_app">
  {{> Template.dynamic template=left}}
  {{> Template.dynamic template=right}}
</template>

<template name="article">
  <!-- article content -->
</template>

<template name="menu">
  <!-- menu content -->
</template>

FlowRouter.route('/post/:postId', {
  name: 'post',
  action: function () {
    BlazeLayout.render('App', {
      left: 'menu',
      right: 'article'
    });
  }
});

Considering I want to separate actual Layout_app from App (because Layout_app can be used by some other ‘components’ other than the App, like Admin, for example), I can not write something like BlazeLayout.render('Layout_app',{

I was wrong, sorry. The bug was caused by some dom-manipulating third-party library. FlowRouter seem to handle nested templates (and even in exactly the way I wanted). Found out by experimenting with the example here: https://github.com/VladShcherbin/meteor-flow-layout-test thanks to VladShcherbin and great news for me (as I won’t need to rewrite everything back to IronRouter).