One Way Window Glass Film - What's The Go To ?

[vdn]

I'm looking at getting some glass film for privacy on a project. I want the stuff that comes on rolls and is easily applied to windows, to act as a private screen of sorts. I've had a look and it seems prices range massively. Is there a go to brand?

Also... I'm reading it is entirely dependent on the lighting inside and out, for it to be effective. Is that the case? (makes sense I suppose)