We've tried a lot of different harnesses. We use different ones for different reasons. I still haven't really found the 'perfect' harness that works for EVERY situation.
Puppia mesh harnesses are our go-to. Every time I try to find something better, or different, we still tend to use them the most. They're super easy to put on, their comfortable for him, and they're cute and come in many different colors. My only complaint is it sometimes seems like it may be too hot for summer (but honestly, he's worn them every summer, and it's never seemed to have been an issue) and they're not good for the beach (sand tends to get stuck to them). They're easy to wash though. And the neck is not adjustable on the regular ones, but the medium fits Jackson very well. They have adjustable neck versions now too though.
EzyDog Quick Fit. Super quick to put on which I love. It seems comfortable for him. I like the neoprene material on it -- good for water activities. It sits up a bit too high on the chest for my liking and I don't like the placement of the buckle (I always have to be careful not to pinch him). BUT overall really like this one.
ChokeFree Leather Harness. I don't use this one very much anymore, but I do really like it. It looks classy, it fits him good, and it's somewhat easy to adjust. It is velcro, but it's impossible to to get out of, because of the way the d-ring has to go through the hole when the leash is on. It's fairly thin leather, which I like and prefer, and the inside is pretty soft so seems comfy for him. Considering getting another in a different color now actually!
We have a few generic harnesses too, the Premier Sure Fit nylon harness in black, a nylon step-in from Petsmart, and we used the Easy Walk harness when he was a pup training to walk on leash so still have one of those.