How do people mount to the inside of their windows? I have some double sided tape about 25mm (1" for you imperial folk), but after a few months it seems to fail, I think the camera (a 70mai) is heavier on one side.
I'm on the "imperial" side and I use the suction cup. That can be augmented with a little dab of vegetable glycerin to improve the seal if there's a problem. The problem with double sided tape is that, since it gets baked in the sun constantly, it dries out pretty rapidly.
I like suction cups. Some use 3m pads or tape, but depending on the permanence type, they can be very very difficult to remove. Suction cups will occassionally lose suction and fall off but all that's required is to clean the windscreen and re-attach. Personally I don't believe the hassle of removing the pads makes them worth it. It's not the end of the day if you have to re-suction a cup.
Suction cups stuck all over your windshield look unprofessional. Don't look like the guy sitting next to you in traffic. Buy a mount for your rearview mirror. Yes, suction cups suck.
TBH, I doubt anyone notices and if they do practicality comes over the professional look for me. SC have several advantages - you can switch the camera between cars instantly, you can remove it instantly for any other reason you may have, you don't risk damaging your screen separating it from the adhesive pads. The disadvantage is SC's do eventually fall off and have to have the screen cleaned and be re-suctioned. That said, it occurs probably once every 6 months so hardly a major inconvenience. However, each to their own. If you never switch the camera between cars or otherwsie remove it or simply value aethetics over practicallity, then 3m pads are the way to go.
3M VHB gray double-sided tape. Will not come off unless you want it to and even then it takes some effort. Make sure to clean the area you are applying it to with some rubbing alcohol first. Dont use suction cups. They always fall under heat or accidents.