I just purchased a Yakima Hull raiser and I looked closely at the competing products. I found that the j rack itself was very similar between products and that the difference lies is the bracket that attaches to the roof rack. It all comes down to picking one that fits your rack. I think the quality of the name brand products is very good and I agree the price of these name brand racks are really high as well. That being said I do not think I would try the low cost racks you are looking at. I am interested in them as racks to mount in my garage for use as dry storage but I would not trust my boat to them during transport. I bet the j rack is as solid as the metal looks but the plastic and metal parts that make up the mounting system may have flaws that lead to a fly away boat. It will cost you 300 bucks to buy 2 sets of the name brand j racks.

If you do use J racks or anything else to mount to the top of an auto, make sure you use a bow and stern line to secure the extreme ends of your long sea kayaks. A lot of people went without them and will never do it again.

I am cheap but piece of mind and safety are worth paying for in this case.

Robert, Visionary