The traditional method of prep and paint still is the only way to produce a superior product.

The quality of your product and its life will only be as good as the work before yours. For the doors strippers work fine then sponge sanding blocks. If a face framed cabinet just sand them down. With regards to paint I would us a real supply house like Bejamin moore over home depot. You will get good advise and better support. If at all possable try having the doors sprayed for you. The finished product will be higher. Cab faces use a high quality china bristle brush to apply then go back over using a foam brush. (that would be if you can't spray the boxes also).