Key takeaway here: Ruby on Rails is the new, hot fad, but apparently doesn't scale in the way web languages should. Dropping ActiveRecord, for example, cuts out the main piece of RoR coolness I still liked.
Seems like RoR is great for getting something out very quickly but if the site takes off then you need to be prepared to take out the very features that helped get you there. <p>So, it comes down to, if you're shooting for something very high traffic (and who isn't) use a faster language. If not, use RoR.