All CMS' suck, a bit like all OS' suck. As soon as you do anything non-standard their inherit flexibility becomes a burden. If you have skills in rails and need an off the shelf CMS find a popular one and use it you like but if you need to create a web 'application' look at Sinatra, rails or whatever but don't use a CMS as the foundation for an application.
Most of all, if my team and I have one take away: Stay far away from Drupal and people that preach its relevance. It is a world of hurt with an 'expert beginner' community. That has cost so many organisations more time and money than they ever anticipated.
Treat ever 'off he shelf' product with a degree of disposability - don't get locked in and never get into the trap that you've chosen 'the best'.