Most of them have variable shade 9-13. Some of the cheapies have only one shade, which could be a nuisance. It's worth checking before you buy.
They should all have passive (works whether the electronically controlled visible light filter works or not) UV and IR protection.
For the difference, I'd go for one of the several £25ish ebay ones, which a lot of people on here use and recommend. For all I know, the JTF one is the same as the ebay ones.