Personally, I don't like it. Too much is left out.
But Aquinas did do his own simplified version. I highly recommend that!!!!!
It's sometimes published under the title "Compendium of the Summa."
But as I say, the complete Summa is not that long. You can probably find used copies of the "Great Books" 2-vols. for just a few dollars at a used bookstore.
It's not like a novel that you have to read from cover to cover. Pick a topic that interests you and read that section. Then move on to another one. No need to be scared of it (except maybe for Cambridge Univ. Press' price).