Gel testing is good because it's a consistent target with roughly the same density/toughness as soft tissue. Not identical to shooting a body, obviously, but it's the only fair way to compare different bullets. If you're watching gel tests on youtube you're not watching anything scientific, though. Proper gel testing has to be done in a very controlled environment. The gel has to be at an exact temperature, and it's only good for one shot. Real gel is denser than the clear gel and barely transluscent, and some hollow points just won't expand in the clear gel, especially if it's hot. I've heard some companies are designing worse projectiles because they want it to look impressive in clear gel. I don't know that it's true but I do know that CCI Uppercut got a really bad rap when it released because it wouldn't expand in clear gel. It's the only time I've seen a legitimate gel test on youtube, because someone wanted to show that CCI Uppercut was a quality defensive round (for .22LR at least) and the people reviewing it and shitting on it weren't doing it right