CTRL+ALT+DEL on very old operating systems, and in the pre-boot firmware environment, causes a warm restart.
In more modern operating systems (for Windows think NT and up) it's captured by the operating system if the operating system is still responsive and brings up a menu letting you for example start Task Manager. It's captured at such a low level that the system has to be pretty hung for it to not work...however...if something is sufficiently wrong just getting those keys captured doesn't mean you'll be able to do anything useful with the options presented to you.
In any case, CTRL+ALT+DEL while booted into an NT and up Windows environment will allow you to perform a normal restart, but it's the same as going to Start > Power > Restart.
Vol Up, Vol Down, Hold Power is only like that in the sense that it is captured at a very low level by the phones firmware. It is essentially the same as pulling out the power cord in how it responds to capturing those key presses. This is necessary because you can't pull the cord from an iOS device, or unplug the battery easily.
The best iOS CTRL+ALT+DEL equivalent is holding Vol Up + Power since that then allows you to perform a clean shutdown, just like CTRL+ALT+DEL on Windows.