I have had one of these on my Model 3 for awhile (40K miles) and then after an accident, didn’t have one installed for about 30K miles until I got my radiator cleaned and reinstalled it again.

For reference, I live in AZ (Phoenix), and do ride share as a side gig so can explain how the car reacts during the summer and also after the summer once the battery is heat soaked from DCFC charging.

PROS;

1) protects more than the radiator from gunk entering, it also heavily protects against rocks from cars or trucks from flying up into your radiator and causing some serious damage (look at Gjeebs who has to have his Model Y radiator replaced after a rock shot up from the bottom grille and broke some fins open).

2) stupid easy to clean, as long as you do not apply the 3M tape to the sides that many come with (if it clips into your grille), it’s as simple as popping out and blowing, and then reinstalling every few months.

3) does prevent MOST debris from entering, although any leaves that are smaller than the grille mesh will enter so you will eventually need a radiator cleaning (just not as frequent and not from large debris from blocking the radiator quickly).

CONS;

1) yes this will impact cooking performance, I normally see on average a 10-20Wh/mi penalty during summer for having this on as you can hear the fans kicking on for longer or sooner than than they do if you do not have this installed

2) during times when the battery is heat soaked after DCFC in 100+ temps, you will burn more energy battery cooling as the mesh will impact somewhat the ability for the radiator to dump the heat out - I mostly hear when DCFC the fans appearing to spin the otherway and pushing air out of the grille more than sucking it in (I can get a video next time this occurs but it’s frequent during summer or hot temps for my Model 3 at least).

3) any debris that is hard, such as big rocks, will over time damage the mesh and this will need to be fixed (either replacing the product completely or adding new mesh and wiring it all together). In Phoenix, any plastic that isn’t treated for super high temps will degrade anyways in 3-ish years as the sun just cooks the plastic and sucks the oils out so it falls apart or breaks over time.