I think you get both higher quality and a better looking job painting with a brush. A little texture from the brush strokes is a good thing, and when you paint with a brush you are looking at every detail, filling gaps and such as you go. The guys who did my house were very good, they sprayed to move the paint onto the wall and then brushed it out, giving both efficiency and quality. (they also painted a first coat all sides of the pre-primed clapboards before they went up without me even having to ask)

If you can afford it ,I would find someone who does it the real way, brush and roll.More paint where it is supposed to be.

In your case, you specifically asked for a brush, I'm assuming. So you should be getting a brush. But there are two schools of thought on this. Personally, I think using a brush, and getting brush marks is one of the best reasons for having your cabinets hand painted. (The other is the option to repaint easily in future.) It's a softer look, and shows a human touch. Some other people (most people, in fact) want a factory-like finish with no visible brush strokes, and using a roller, or better yet, a sprayer, and a self-levelling paint. So maybe they assumed you were one of these people. But that should give you a finish without ANY marks, not roller marks. So it sounds like they didn't succeed on either count. Whichever look you're after, talk to the boss. It's perfectly fixable.

I dont mind spraying outside, but, unless you are experienced with a sprayer, I wouldnt spray inside. Use brushes and rollers, and take your time. One room at a time. It does take time to remove wallpaper, and clean and prime the walls, so be p repared to live with rooms undone for quite a while.