I bought the Domino kit and I use every thing in it on various projects. The suggestion to buy the tenon/cutter assortment is right on. Without the various cutters, you are missing out on one of the Domino's big strengths.
Of course, you will need a good vac as the Domino generates a lot of debris.
The Domino is a wonderful tool, but it requires good technique to get good results. I advise watching Halfinchshy and New Brit videos and then practice on scrap. Reading the supplemental manual before you power up the tool is a really good idea.