I just go with what protects the hoof a doesn't rub ??
I use Lemieux soft shell overreach boots for riding, and rubber with velcro or pull on for the rest of the time/turnout. He's managed to take a variety of boots off over the years, but never had a safety issue if they fit right.
Agree that fit is the most important thing to making a boot suitable for jumping - too tight and it will cause chaffing, too big and it may get caught up in your horse's overstep. However, not all velcro'd boots are created equal. I feel this is the one element that lets the boots down. I started with the most simple - overreach with simple 2 velcro straps. Everything stuck to the velcro, to the point that it didn't stick anymore, after a couple of weeks. I am on the Le Mieux with fluff around the top ones now and the sealing element of the velcro is better as it is one piece, not 2 as in the previous boots. Ideally the plain boot without velcro is the best choice, but quite a faff to get over the hoof and shoe of the horse each time you want to use them.
I agree with not all velcro is created equal. I've been satisfied with the Lemieux boots though. I had some from Horze that did not have good velcro.
The pull-ons are easier/more stretchy if you get the natural gum color. The black ones are more difficult. I have left pull-ons on the horse 24/7 and he's been fine. He easily rubs but these are no problem.