I think it is reasonable to say the shuttle was supposed to "get into space on the day it was planned to launch".
I do not have data on it, but using that yardstick or even the more lenient "get into space within a month of the planned date", I think it was not very reliable. I also have the impression (but again: I do not have data) that the Soyuz is way more reliable in that respect.
I do not have data on it, but using that yardstick or even the more lenient "get into space within a month of the planned date", I think it was not very reliable. I also have the impression (but again: I do not have data) that the Soyuz is way more reliable in that respect.