For interior paint I prefer the semi-gloss, provides a very subtle sheen and is super easy to clean -no flaking, chipping, etc. I've painted a lot, and found that Sherwin Williams Ovation paint has been the easiest to use, and provides the best coverage. I even painted my ceilings with it and WOW! I was done it no time at all, with perfect coverage.
A fellow (actually lives in the same neighborhood) by the name of Wayne Hickey (843-655-0366) painted the ceilings and most of the walls of our house in February 2017. He got paint all over my light fixtures, all over my trim around the doors, and had visible lap marks everywhere on the walls. He came back and rectified some of the problems, but not all, as I have noticed as I have had time to look more carefully at the work he and his assistant did. His assistant had no idea (not a clue) how to roll paint on a wall or ceiling. Some places were not covered. He said he would pull nails for pictures and then re-insert the nails exactly where they were. This he did not do as he promised. He painted over the nails. His assistant had no idea how to use a paint roller. I have painted all my life, and would have done this work myself, but I just had a full knee replacement and the other knee is in bad shape. I just could not do the work. Wayne is a pleasant and congenial individual, but he can not cut in a ceiling or wall to my satisfaction - not even close. He should have a putty knife and wet cloth with him all the time to correct any paint that might get applied where it shouldn't. That is something I always did as a painter. I would not recommend Wayne to paint anybody's home.
Thorough preparation is essential to ensure a good finish. Contractors might have to fill cracks or holes and remove old paint if it is badly worn, peeling or flaking. They remove all paint and apply a suitable primer to the bare surface. If the existing paint is in reasonable condition, they clean it and rub it with abrasive material to provide a key for the new paint. On new surfaces, such as bare wood or fresh plaster, they apply a suitable seal, followed by a primer coat.