Some are much better at reducing IR than others. You also have to decide how dark you want the film. FWIW, the 3M Crystalline tint has about 200 layers for a broad spectrum of reduction, and it doesn't have to be super dark to accomplish the fact. It's harder to install than some, and the shop must be certified by 3M to buy the stuff, so you may have to look a little harder to find a shop that can install it. Not saying others are bad...they each have their good points.
2014 i3 BEV, 2021 X5 45e
(The i3 will be sold soon, <17K-miles, interested?)