Ok, I'll admit, this may sound a bit trollish, but if PHP is not one of the worst languages, then what languages do you rank below PHP? C comes to mind, not as a bad language itself, but lack of web libraries, but that's about it.
It has messy stdlib (gets()!) and lots of features that you can shoot yourself in the foot with (software security would look very different if it had arrays like D).
The C standard library is very clean. gets is left in the C89 and C99 standards for backward compatibility an deprecated right now. Nobody uses gets nowadays.
I don't think PHP is a beautiful language. But that's beside the point. Sometimes you need a hammer, sometimes a screwdriver. You don't dismiss a tool because it's not pretty.
Hammer and screwdriver are equally ugly/pretty. But that's beside the point - it's not the ugliness of php that puts people off, it's the clumsiness and awkwardness of the tool.
Is Instapaper merely adequate, or is it better? Would it have been that much better if it was constructed in Rails?
IIRC, Instapaper's a PHP application. I could have mentioned a larger site, but Instapaper was probably a better example, since it's quite popular with HNers.
Well, I hate Rails so that wouldn't be my first comparison.
But yes, it would probably be more easily maintainable if written in a better language, and the developers would be able to add new features more quickly.
To comment based on your metaphor, the problem is not that the screwdriver/hammer is ugly. It's that the grip doesn't feel right and it's unbalanced. You can turn the screw and drive the nail, but it takes more effort and might leave your hands scraped up.
