It won't look bad. Only do a few boards at a time though, keep a wet edge at all times. The best way is to use a 4" roller to apply the paint and then back brush it out. Don't work in the sun.

I did what you are planning to do - hire out the work on the upper level and do the painting on the lower level myself. My house is wood with metal guttering.

The professional painters who did the upper level used only brushes, and so did I. Switching between a roller and a brush would have been awkward for me. I don't think it would have saved me any time.

I thought the purpose of paint spraying was to save time, not that it was any better than applying with a brush.

Thank you both for your replies. That helps a lot and relives my mind that I can continue with the original low cost plan. SW is having a 40% sale in April and I plan on doing it then.

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)

I can paint a house twice as fast with a roller and brush, and I know there's plenty of paint on it.