I asked myself the same question. I also added brining to the equation and did a blind taste test. Here was the test. I took three half slabs of baby backs and slathered one in a rub, one I marinated in apple cider, garlic, and black pepper, and the third I did in apple cider, garlic, black pepper and salt (a basic brine). I put all three in separate ziplocks in the fridge overnight.
The next day I rinsed off the ribs in the marinade and brine and patted them dry and applied the exact same rub that was on the first slab of ribs. Then I cooked all three identically. I've done this experiment twice now. Once on my in-laws (who, God Bless them, are my guinea pigs a lot) and then on my dad. Each time the tasting was done blind. The tasters had no idea which rib was brined, marinated or rubbed. All they saw was three identical looking ribs.
The results were the same every time. The ribs with the rub were good, the marinated ribs were much better and the brined ribs were even better but not heads and shoulders better than the marinating. The simple results were a marinade improved the ribs a great deal over a rub, and even a rub that was applied the night before.
Prior to this I'd marinated a few times and brined a couple times and really couldn't tell if there was a difference from my ribs that I only did a rub on. But with no control group, it's very hard to compare apples to apples. Once I did them side by side, the results were startling. I brine every single time now. Doing them side by side is the only true way to judge the results.
But that's just me. Maybe you will do the experiment and come up with different results. I wasn't sure myself which is why I did the experiment a second time, but after the second experiment, I'm sold.
