At RailsConf, I had the opportunity to speak to a lot of people about Merb. I also listened to DHH's keynote, which touched on some related concepts.
People coming from a Rails background, and are looking at Merb for the first time, wonder why they should throw away the phenomenal efficiency improvements they got from switching off of error-prone, tedious configuration scripts for another set of configuration when Rails makes all the decisions for them. DHH made this point fairly explicitly in his keynote. To sum up, he argued that people only think they want to make decisions; instead, they really want to be given a fully working, homogeneous solution so they can get on with their business.
Believe it or not, I agree.
The devil, as they say, is in the details.
In the real world of software applications, the monolithic solution doesn't always fit your needs perfectly. That's why Rails implemented, very early, a plugin architecture, which immediately reduces homogeneity.
You see, Rails is like a pre-fab house. For people who have gone through the pain of constructing a house before, pre-fab houses are very appealing. Suddenly, there's no need to spend time with architects, contractors, or painters. You just place an order and you get a house. It seems great. You can get the furniture you want, or even repaint it.
And when you need to bring in a contractor for routine maintenance, you can have your pick of contractors. Because your house is the same as every other house they worked with. But soon you decide you want a window. Unfortunately, your house is pre-fab, so you pick up a hacksaw and hack away. Everything seems great until the first time it rains. And the water starts coming in.
Undaunted, you pick up the phone and call all those contractors you worked with before. When they get there, they take one look and let out a sigh. They have no idea how to deal with the glaring mess you have made for yourself. After paying a hefty bill to get everything fixed, you tell yourself that it's still worth it. After all, you're still ahead on time compared to Andy down the block who had to do everything from scratch.
But you see, there's another option.
At a builder's show, you see a shiny booth run by a new company called Mer Builders. They have put together a house kit that allows you to put together your house quickly and efficiently. And when you want a new window, you just pull out one of the wall blocks and replace it with a window block. Quick and easy.
But wait, you are probably thinking. I still need to put together the house. That smacks of all the pain of building a house from scratch. It's not as bad, but I'll still need to decide what pieces I want, figure out how they hook up, hire someone who knows how to put everything together, and more. Who wants that. A pre-fab house will do just fine, thank you very much.
As you turn to leave, the Mer Builders salesperson calls after you. You see, it turns out that they understand that you'd rather not have to make all those decisions yourself. And they've put together a starter kit that looks kind of like the pre-fab house. You can order it today and have it delivered tomorrow. But when you want to replace a window, their network of certified Mer engineers will simply and easily swap out a wall block for a window block.
Heck, soon enough you'll probably be doing all sorts of customizations on your own.
The moral of the story is... Use Mer Buil... er... Merb!