I will admit (and my nickname will prove it) that I live in the world of ASP.NET and that I quite like it there. But I am not a stick in the mud, if Ruby on Rails can really do it better then I am more than willing to change. But there is one thing I cannot do without (and neither can my clients as it is what all of them want / use) and that is a portal engine. I use DotNetNuke and I like what it does for me, but I don't like making new components as it is time consuming (Yes, I agree this is the part that got my attention with Ruby on Rails), so if Ruby on Rails had something like it I would definitely look at switching and if one doesn't exist, I have been looking for a project to sink my teeth into with RoR, but I cannot see an easy way of making components like DotNetNuke has, and probably I cannot based on the whole hierarchy that ASP.NET places upon components that is completely lacking in RoR (apart from building one, but then that would basically break RoR). This is one part of ASP.NET that I like very much, the simplicity with which it allows me to include controls and handles directing messages to those controls. So since RoR is based on "real world implementations" here is a real world scenario for some input.
Well, for a portal I'd go with Plone or something. Rails is not a CMS framework.
Actually if you go to the widgets site there is the basis of doing "components". Also look at "partials" as well.
I use tabnav for menus, rolerequirement for role based security, and active scaffold for crud.
Checkout mentalpagingspace.blogspot.com, to give you a idea, and the links.
I looked at a few cms, but I find almost all of my content is dynamic anyway, and for most things I need to do its a plugin, and takes me only a day to master.
I find .net to be bloated compared to vb6 era, and that ruby (And rails) returns me to the level of effectiveness of vb6