That's a tough choice. I love them both. Legs & Glutes feels almost like an endurance workout for me. I like the different types of exercises in it and that it doesn't do only the standard squat, lunge and leg press. Gym Style Legs is also great. I like using the resistance band. They both are different and challenging workouts (just the way I like them.)
I like GS Legs better but will never part with L&G. I like to pull out L&G when I'm bored with my routine but need a lower body workout. I like it b/c of the fast pace and I can get my heart rate up and keep it up but my favorite out of the two is GS Legs.
I like GS Legs better because the order of exercises makes sense - no going back and forth. It has straightforward lower body exercises that get the job done - squats, lunges, plies, deadlifts, reverse lunges, and awesome floor work.
I prefer basic, to-the-point strength workouts, so keep this in mind while reading my recommendation.
I like the straightforward nature of GS Legs but I hardly ever have time to do it in its entirety so I end up using L & G or even PLB a lot more often. If time is an issue for you, choose L & G. If not, go with GS Legs.