rails: always have had pains with maintaining apps, but will always love ruby. very much stays true to its convention over configuration philosophy. if you stick to (or sometimes, can even find) the "right" way to do things, it's very smooth. if you start down a wrong path things can get painful quickly. luckily there's a lot of resources for 90% of things you'll want to do.
node/express etc.: basically the flip side of rails, a lot of doing it yourself. there's a good ecosystem but i've sometimes found myself lost in a sea of options.
meteor: last year or so i've been doing more and more stuff in the framework and it's a good mix of both of the above. it's reliant on Mongo so a lot of RDBMS techniques are useless which can cause some pain. ecosystem is pretty young so there's a lot of the node-esque soul searching.
like runjake said, i'd try each out. have found the following somewhat useful:
* ruby/sinatra: http://code.tutsplus.com/tutorials/singing-with-sinatra--net... (express, later, was inspired by sinatra which is a quick library to learn)
* rails: http://ruby.railstutorials.org (the "definitive" starting point i suppose)
* node/express: http://scotch.io/tutorials/javascript/build-a-restful-api-us... (this is just an API but generally gets the main ideas across)
* meteor: https://www.meteor.com/install ("Discover Meteor" is the best resource to start, but it's not free)
Outside of the Rails tutorial, should probably be able to get a rough sense of each in a day