While not an official "expert" I do have a lot of experience with window tinting. I've been doing my own cars/trucks and for friends for years. By years, I mean since the 90's, so around 20 ish years.
As for the brands mentioned. I've heard of SunTek but have no personal experience with their product. Wincos is a new one to me. I looked up their site, and they're pretty vague. No real description of "why" their product is allegedly superior to any other film. They don't say what it's made of, how it's layered (yes tint is layered), or anything specific. All they say is that it's made with "selective organic coatings
". Okay, so what organic coatings, and why are they superior to ceramic, aluminum, carbon or other materials used? Or are those the same organic coatings they're referring to?
I don't know. Like I said, I'm no official expert so take it for what it's worth, but the Wincos sounds like an up-sell. From what I can tell they're not offering anything more than other quality films are offering. To give you an idea, the "budget" SunTek film also blocks 99% UV light, and depending on the film you chose (they have several options) they also block the same 92% IR light as the Wincos that is supposed to be "premium".
I personally use Concord Window Films. They've been around since the early 80's, and they've got a wide variety of films. I use their automotive security film, but you can get more affordable films if you don't want to go that route. The down side is that you have to put it on yourself, or maybe find a shop that will use your film. They don't have a shop that installs the stuff. They make the film, they're not in the installation business.
One major consideration for any film is heat. Mopar is using laminated glass on the side windows now instead of just the windshield. This is important because the wrong film can cause your window to break due to heat differential between layers.
The short version is that some films absorb more heat than others. They all technically absorb some and reflect some, but the concern is how much is absorbed. If the film absorbs to much heat, the inside layer of glass that it's attached to will expand quicker than the outside layer of glass. If the difference is enough, the window will shatter. You want to contact the manufacturer to confirm their film is safe to use on laminated glass. Make sure you contact the manufacturer, NOT the installer. Installers rarely know technical aspects of the product, and are more likely a random guy who found a job at an install shop. The people at the mfg who develop this stuff have degrees, and a full understanding of how it interacts with light, glass, etc. Not saying that one person is any better than the other, since the people at the mfg likely have no idea how to actually apply the film to a window. For film details ask the people that develop it, for install details ask the people who put it on cars daily.
Anyway, going back. SunTek is likely sufficient. I don't see anything special about Wincos that deserves a premium price. It sounds to me like a sales pitch.
FWIW, the Concord film I use are cheap by comparison to having a shop do it for you. What you're usually paying for at the shop is their installation expertise. The films aren't really that expensive. It takes a lot of practice, and a lot of messed up applications before you get good at it. For as long as I've been doing it, I still have to redo a window every now an then. Though it's much less common than when I started. Anyway, point is a roll of Auto Ceramic is roughly $100 for a 50 foot roll. Once you get good, you can do a lot with that roll. When you're new, you can probably do 2 Jeeps with it. At the very least you should be able to do 1 WK2 and still be cheaper than paying a shop.
If anyone is interested, I posted a how-to thread on tint installation. Here's a link → Tint How-to
And just for grins, here's 3 that I've done.
My Charger RT (that I traded for the Jeep) my Ram Sport, and my Jeep. The Ram and Jeep have 50% VLT front windows, and 10% VLT rear. The Charger had 50% VLT front windows and 25% VLT rear.