Personally, I don't think it is effective or worth my time. I am in a similar situation (3.5 year old and almost 11 month old) as you and I just don't have the energy nor do I want to make the potty be a battle of wills. I know he is physically capable of going on the potty, and he knows we are fine with him staying in diapers (like the baby) until he is ready to use the potty. I let him pick his "prize" for making poop on the potty (He had been peeing on the potty no problem until baby was born) - now he gets 2 skittles for every poop session. I remind him if I seeing him heading towards one of his "spots" and also at times when he usually goes. Most of the kids at his school wear underpants, but they are fine with diapers there so it's not a problem.
I think you need to decide what is right for your family. If you NEED him out of diapers, then you need to PRAISE the heck out of him when he is successful and downplay the misses. Have a sticker chart, let him pick a prize, tell everyone you know about what a good job he is doing using the potty. Pick a weekend, stay home and have him go nakey from the waist down. Sit on the potty with him, and read potty books.
Speak to your pediatrician about it, I think that developmentally it can take boys until about 4 years old to master potty learning.
Good luck!