First off your questions are very subjective. What I mean by this is
that there are many, many variables that affect how long it takes to
develop software. For example, it would take a programmer,
significantly, longer to add a backing database to a web site if he
had no pre-built tools to work with.
It's completely unfair to compare PHP, alone, against Ruby on Rails.
There are frameworks written in PHP that are similar to Rails in that
they provide the web framework.
I have only been working with Ruby on Rails for a short time. I come
from a Java background. I've been writing web applications in Java
using the WebObjects development framework for around 6 years or so.
Although I really like Java and WebObjects for building web sites, I
find it pure joy to work in Ruby on Rails.
I love Ruby as a programming language, and Rails is one of the
greatest web frameworks I've ever encountered. Now here's the tricky
part: as of today, I can build sites faster in WebObjects than I can
in Ruby on Rails. You ask, "Why is that?" The simple answer is that I
know WebObjects inside-and-out. I don't have to pause for long
periods of time to learn how to do something in Rails that comes
naturally to me in WebObjects.
So then why my interest in Rails? This is also easy to answer. The
things that I "have" learned about Ruby and Rails make it much easier
for me to accomplish those tasks than building the same solution in
Java and WebObjects.
The reason for this has a lot to do with the fact that Ruby on Rails
has many of the best-practice methodologies "baked" into the
foundations of the framework. Things like convention over
configuration, automatic object-relational mapping, strong focus on
agile programming techniques, test driven methodologies, and REST
baked into the framework.
Ruby on Rails has an elegance that is unmatched by any other language/
framework I've ever work with. This elegance helps keep a programmer
focused on what makes the application unique and useful to the
customer. This results in a highly maintainable code base. Such code
bases are naturally easier to extend to add new functionality.
Here are a few links that I hope you will find useful:
Bob Green wrote: