You might be money ahead to remove the old doors/jambs/casings yourself and have a pro install the pre-hungs. If you have experience hanging pre-hungs, then I stand corrected, but if not, leave it to a pro as even pre-hungs have variables concerning problems with the openings that you can run into that a pro knows how to deal with. They have all the tools and are in and out efficiently. If you aren't experienced at trim work, you might have them case them out as well. Seek out a reputable finish carpenter and get referrals from suppliers, door outfits, folks you know who have hired one in the past, etc.

What problems have you experienced with the paints? For me, I use Behr, BM, SW and others with good results. But, I always spend more time on prep than paint. First wash the walls with dawn, it has good grease cutting capabilities. I use a roller style sponge head to wring out as much solution as possible. Rinse using fresh water. Make sure the mop head is new as well. Touch up any holes with a good spackle, I like drydex. sand smooth and spot prime. Prime the walls. Yeah, I know they all say paint and primer in one. I don't care. Most walls haven't been painted in a wall, why waste paint on your first coat adding moisture to the wall? Buy the best roller cover you can for the finish you want. Before using it, wrap it with painters tape and then remove the tape. Notice all the loose fibers? They won't be on your walls now. Now, you are almost ready to paint. Run the roller cover under water to get it wet. Wring it out well. I roll it out on one of the walls. The reason for doing priming the roller, is that it will accept paint faster. Make sure your paint is thoroughly stirred. Strain it as you pour it into your pan/tray. And your cut pot. Never dip a brush into the paint can, you will introduce contaminants. Now, you are ready to paint. Hope this helps, let me know your thoughts.

Yes, we painted all in a bright white, it's called chantilly lace - Benjamin Moore. Doors and trims are shiny, and the walls matte. (To be more exact it was our intention to paint all the same... The part where the contractor in fact painted some rooms with just the basic white (no chantily lace in it), it's a different story => only pick contractors with very good recommendations from people you know, not 5 star rated from Google!)

We also bought a house a couple years ago that have these doors.... but they are painted white. If yours were solid wood I would not paint but since they aren't, painting will update the look ... a little. I think you need to live in the home for awhile before committing to changes that cost a lot. My concern is that if you change to the shaker doors you like you would also have to change all the door trim and floor molding to a simpler look to match. The cost could snowball especially if you can't diy and have to pay someone to do everything. Even painting is a major cost if you aren't doing it yourself. Is it your forever home? It could be worth your time and money to change if you plan on staying here awhile. But if it is a long time home you also have time to make changes in stages you can prioritize. Our home IS our forever home. I'm not crazy about a lot of things but changing the doors are far down the list of things I want to change. First is kitchen appliances, changing flooring and hopefully someday changing our master closet/bath. I hate the layout but at this point don't know how to make it better. Because of that it is the only place in our house that hasn't been repainted. But my husband tackles a lot of our home projects. Time and money.