What some people need to understand is that this is not a question merely about preference. It is a question about functionality in-game. The functionality I am speaking of is the ability to bhop. The higher on the skill-gap you go, the more things like movement, crosshair-placement, etc. matter. Bhopping is an essential part of high level movement in CS. Watch any pro match, and you will see the players utilize bhopping in one way or another at numerous occasions. There is a reason for that. Bhopping can give you an advantage in many situations, by saving time, being evasive etc. To simplify what bhopping is for those who do not have a clue: Its stringing together two or more jumps.Examples of practical uses: 1) A proper bhop will give you more movement speed that running with a knife, enabling you to save time traveling from A to B if you do it correctly. Thus giving you a surprising edge over your enemies, they might not be ready. 2) A more simple example is "bhopping" from inferno A site to car to apps. Doing this while stringing together jumps easily saves time.
Some people argue bhopping is "easier" with mwheel. This is a huge understatement. With space, stringing together more than two jumps in a row is practically impossible on a consistent basis. This, in a competitive scenario, renders "space" useless compared to its inferior "mwheel" competitor. With mwheel, timing the jumps to bhop properly becomes humanly possible. I will not go into the technical details as of why, it just is that way and I am sure you can find out why if you bother.
So what is bhop and what use can it possible have in a competitive 5v5 match?
At this moment the poll says it is about 56/44 in favor of "space" bound to jump. As someone who has been using mwheel to jump naturally for years (only in CS tho), this was at first a shockingly high number of space-users. Now, given the crazy and still ongoing growth of CSGO, it might not be that surprising. There are so many new players who have not even heard of bhopping, let alone figured out how to use it in a competitive env