The Tiny Core project was started in 2008 by one of the refugees from DSL, so it isn't much of a surprise that it follows the same ethos of trying to get as much as possible into the minimum amount of space.
If anything, Tiny Core has taken this to more of an extreme, completely savaging the package base to create just about the smallest distribution you could still consider to be a Linux OS. While this is great news for those trying to fit the OS on to ancient hardware or embedded devices, it does inevitably mean you'll need to do more work if you want to do anything other than boot it up and look at the X display.
Fortunately, there's an app installer that enables access to the large repository of TCZ packages, so you can easily install the apps that you want. Dependencies are handled, but obviously, if you choose to install something like Firefox, you're going to see the disk space taken up by this distro ballooning to new levels. But you will have to install something, otherwise a few system scripts and a terminal will be your only company.
In some ways, it's not quite so useful to have such a diminutive distro. There may be some specialist cases, but for general use, most people can easily spare, say, 100MB of space. Sure, you can build on the Tiny Core install by adding applications, but it may have made things easier to aim for a slightly higher target to begin with.
But that's to take nothing away from the remarkable achievement of creating a Linux install that fits inside 10MB of space. It's easy to see Tiny Core becoming the basis of many specialist application distros – if you can get the base install down in size, it leaves you with a lot more room to pile on your custom applications.
Verdict: Tiny Core Linux