Alright, let's clear some things up.
First, DAC does not stand for "Direct Attach Cable," it stands for "Direct Attach Copper." DAC cables are generally used for inter-rack (not intra-rack) connections; for example, from top-of-rack switches to the machines located in that same rack. This is because name-brand DAC cables are generally cheaper than name-brand SFP+ transceivers.
Second, the data that goes into a DAC cable on one end is exactly the same when it comes out the other end -- they're not like crossover cables or anything like that. SFP+ transceivers and fiber will work just fine directly computer-to-computer without a switch. In fact, some manufacturers sell short, pre-made "active" optical cables meant for short runs instead of DAC cables just because optical cables are less bulky.
So, to answer the original question: The only difference is that DAC cables tend to be short. Other than that, no.
And, the follow up question: "Do we need to have a special transceivers for "cross" the data like we have on RJ45 or not?": No. DAC cables and SFP+ transceivers can both be used in connections from computer-to-computer without a switch.