Will it make it faster or slower?

The real value of upstart is that it also handles the hibernate and suspend processes. Instead of having separate, semi-magical scripts to handle the suspend process, upstart uses the same scripts as it would if it were shutting down whatever needs to be shut down. That way you know that everything's shut down cleanly and the developer hasn't patched a bug in one place and not in another.

In fact, you can extend this to most state transitions. Turn the wifi and bluetooth off to save power or to work in an airplane? Upstart will do the same things as required if you were shutting down the whole laptop. Shut down the USB devices to save power? Same thing. You get to use the same scripts all the way through, meaning everything is much more robust. And those start-ups start everything up in parallel, just like your boot sequence.

So upstart is great for speed and flexibility whether you suspend, hibernate, shut down, or whatever.

Have fun,

Paul