Talking about generalities, mirrorless cameras are smaller and lighter. The small cameras are much better for traveling light. Technologies in a mirrorless camera are superior to what you could find in a dSLR.
AF is superior with a dSLR camera when it comes to action or wildlife photography. Modern mirrorless cameras continue to improve their AF system and sooner than later their AF will be as good as that on a dSLR camera.
There are other advantages to using a mirrorless camera but I pointed out for you what I consider important in both cameras.

Rant time: "SMRCS" (subject matter repeat complainers syndrom) - The sad part of discussions like these is that (I didn't count) half the posts are complaining about the subject matter rather than answering with helpful information, and we are only two pages in as I type. I'm not the forum police, but I do find the "SMRCS" (subject matter repeat complainers syndrom) much more annoying than folks who ask questions that have been asked before. For those who no longer want to hear about the Pros/Cons of two major camera operating systems, why participate? For those who do want to offer up the Pros/Cons of any particular subject, please participate. If you are not interested ignore the post, don't complain and muck up the waters, or worse make the OP feel like a fool for asking.

As for the search engine pulling up solid answers for questions like these - it doesn't work that well, the emphasis is on the title and this often misses a great many posts (unless I haven't used it correctly).

Now, if you want to bitch about something, or bitch at me, open another thread and complain about olemikey!!! I can handle it, I love a good debate, I love a good argument, and I try to make sure I'm at least somewhat informed prior to posting. Don't be offended however, if I ignore the post (LOL) !!

Now, on to the question - It would seem by now that for those who want to know the answer to the OP's question, that someone somewhere must have put together a summation of the arguments for and against each operating system, and that is a story that would be worth the read. AS FOR ME, I would like to have one of each, until such time that something better than both comes along; 5 -7 years down the road, perhaps?

It's kind of counter-intuitive, but on a ML camera the AF sensors must be integrated with the image sensor which presents certain design challenges (chip area limitations). On a DSLR the AF sensor (at the bottom of the mirror box) is totally separate from the image sensor and the AF sensor photosites can be larger and more sensitive with dedicated subprocessors ...but frankly I am surprised with the piggy back mirror flapping around how (1) performance can keep up at up to 10-12 fps and (2) how the delicate mirrors don't unhinge with all that pounding at those frame rates.