I find it annoying, but then again it may be usual for people to use their phones continuously enough to drain the battery to the point where they shut off, then scramble for power and have to sit and wait for the phone to turn back on.
if the phone booted more rapidly, I'd turn it off during movies instead of just turning it to vibrate.
if you can boot fast, then you can power off and reboot instead of doing a suspend (with all the overhead of saving your entire memory to durable media)