So I've always had trouble deciding what kind of "dog containment" mechanism I want to use on Mason. I started with regular collars (and bought tons because I like changing them up) and then switched to a single martingale collar for a while to help to teach him to not pull on a leash. If you don't know what martingale collars are, here's a good explanation.
Here's a picture of Mason in his bandana print Lupine brand martingale.
I liked them for a while, especially the fact it has two loops--one for identification and one to clip the leash and that tightens the collar when they pull. I was starting to have issue with it, because Mason still sometimes pulls when he sees certain things (sheep, or when he wants to run since I run with him in a certain area but sometimes I just want to walk so that isn't always conducive to what we are doing) and I felt like he was choking himself, and it wasn't to teach him anything anymore, since he wasn't pulling constantly--just when he thought he should be getting to something (IE herding sheep/running) so I decided to try a harness.
I have heard mixed reviews about them, some people say they encourage pulling and others say they give more control to the person. I've found them to be very helpful, and I just FEEL better about a harness. It's not putting any pressure on his neck, just his whole chest area, and when he does pull he's not really able to since the whole harness is around his body so he stops.
I got Mason a step-in harness, which doesn't also wrap around his torso/belly, just around his arms and his chest. It's Dog Whisperer brand, which is SO lame in my opinion but it was the only pattern I liked and it was made of a soft floppy material, and a lot of the others were stiff and I didn't want them to rub up against him and rub his fur off or be uncomfortable. Here he is in it:
He doesn't mind it at all. Then again, I always make him wear bandanas and shit, so he's probably used to random things being put on him. But I think it works a lot better. I wish it had an extra loop to put his identification on the front, but I'll probably just put his collar on him too if we go somewhere unfamiliar or just get an extra tag for the loops that attach to the leash.
It doesn't restrict him from running or rolling around, and I'm not as concerned about it getting caught and choking him or something...I don't know, I was really weirded out by the concept at first but I find myself more satisfied with the harness and I feel like it's a lot safer as well.