I currently have two blue Jackson wheelbarrows. They are my most used wheelbarrows and the only wheelbarrows I use for hauling dirt, wet cement, bricks, rocks, green firewood rounds, or anything heavy. They are noticeably stronger than other wheelbarrows I have tried and they flex less during use. The extensions on the back ends of the support legs are a nice feature, because they make the wheelbarrow less likely to want to tip backwards (handles to the ground) if I have to park the wheelbarrow on an upward slope. The knobbier tires also grip better on slopes that might be slippery. I top off the air in my tires once each spring and that's all they ever need. Never-flat tires are nice in theory, but I have yet to find a version that works well all of the time for heavier duty jobs. They are often too hard and/or narrow, so the tire gets bogged down easily in softer ground or it is more likely to make compression tracks in softer soil when hauling something heavy. Alternately, the tires are sometimes too soft and spongy so the tire itself compresses too much when carrying heavy loads (like dirt) which increases the drag you feel while pushing the wheelbarrow. In my opinion, never-flat tires are only a good choice for light/medium duty wheelbarrows that rarely have more than 200 pounds of weight in the tub.
My second most used wheelbarrow is a 10ft3 plastic tubbed dual wheel model. I don't remember what brand it is because all visible branding disappeared years ago (I'm thinking it's True Temper). It is a great light/medium duty wheelbarrow for doing general yard work in landscaped areas. The extra large tub volume is perfect for hauling leaves, bags of fertilizer, pruned branches, grass clippings, yard tools, bark, wood chips, seasoned firewood, etc. I like having dual wheels on that wheelbarrow because they help prevent the larger wheelbarrow tub from tipping over too easily if bumped. That being said, dual wheels are pretty useless for narrow single track type walking trails, rockier areas, or for working on sideways slopes, because it's harder to avoid the holes or bumps and the wheelbarrow will always tip to match the slope you are walking on.