Pointability and shootability are two separate things, one does not define the other. Glocks do feel strange compared to the grip of a double stack 1911. Glocks tend to shoot amazingly well vs the strange to many grip angle. In my experience with an XD 9mm and an Glock G17, when each is drawn from a holster, shot at a IPSC cardboard target, 5 rounds as fast as possible, the Glock G17 had a better grouping or no misses vs wider spaced groups with some misses with the XD. Speed was basically the same using a timer, between 3.2 to 4.3 seconds for both pistols. In my limited experience in IPSC Production class, I have noticed a large # of Glock pistols, and more shooters using the S&W M&P now than 2 years ago, I have only seen / shot with one shooter using an XD.
Of your choices I would go with the G21 , M&P then the XD in order. I would rather shoot in .45 a 1911 or the SIG P220, but that is my preference. If you go with the Glock you will enjoy a larger parts & accessories selection and much better and cheaper magazines than either the XD or M&P.