on reflecting how to talk with prospect customers on technologies for web applications, what are important requirements for chosing a specific technology? I am biased towards ruby on rails, but the code base and community of PHP is larger, while the user experience of flash sites is often an advantage to the segment of higher paying customers.
how would you argue for or against the usage of a technology in general? for ruby on rails in particular?
One of the best selling point (IMO) for any technology would be your personal level of expertise with the given technology ! Show your potential customer what YOU are able to do with the technology, show them your implication in the developer community, talks you have given etc.etc.
Straight off the Rails site:
“Ruby on Rails is a breakthrough in lowering the barriers of entry to programming. Powerful web applications that formerly might have taken weeks or months to develop can be produced in a matter of days.”
and...
“Rails is the most well thought-out web development framework I’ve ever used. And that’s in a decade of doing web applications for a living. I’ve built my own frameworks, helped develop the Servlet API, and have created more than a few web servers from scratch. Nobody has done it like this before.”
... and more. If you're looking for a sales pitch that up-sells a given technology, start with the basics.
My advice would be not to sell a technology if you don't have to.
If a client asks you about a specific technology, ask him why he wants this particular technology or what he expects from using this over the other. I often find that clients have no clue about these sort of things (and they don't have to), but they usually do have a clue about their project.
The technology you choose should fit the project. The client usually has a vision and a business case he wants to see realized. The technology is just a means to this end. If the technology can realize the business case within the client's budget, fine. It doesn't matter if it's PHP or Ruby or Flash or Technology X then. As long as the technology meets the project's requirements, you can pick it. If you are biased towards RoR and feel comfortable programming with it, use RoR.
If you have to argue for or against a technology, do it over project metrics. Tell your client, you are used to technology X and can deliver in Y days instead of Y+Z. Tell him, developers for technology X charge smaller hourly rates and thus development cost and maintenance cost will be cut by Y percent, resulting in less TCO. In other words, tell him how technology X benefits the project in measurable terms.
On a sidenote, since you mentioned the UX of Flash sites, here is from my experience:
I wait for 20 seconds for this whole damn thing to load. I've learned from previous experiences with flash sites, that this is the perfect time to disable my speakers, so I don't have to listen to the music I didn't ask for that will surely come. I then spend 20 more seconds watching the UI fly in with all sorts of fancy animations. I don't want to see them, but the developer felt if he put effort into building them, he has to make sure I cannot skip them. He also felt that standard components lack his artistic vision and thus I have to relearn how the UI works. After another minute of searching for the information I came for, but only finding fancy marketing terms that tween across my screen with even more fancy animations I didn't ask for (likely to appear with sound fx I didn't ask for either - thank god I'd disabled speakers), I leave for the competitor with a valid and simple HTML site.
EDIT I am aware that not all flash sites are worthless multimedia horrors. If you are a flash developer and did not create an abomination as described above, I thank you from the depth of my heart.