After reading and browsing through several threads about tint, here's a bit of my personal opinion base on what I read and my brief visit to 2 reputable shops. Some of the technical information and package can be found in this threads, website, and other forums. I hope any sellers from these 2 companies is fine with it.

Firstly, I owned a 10-years old car with a reputable tint (Air Cool) which applied since then. That time, my tint cost around 1.5k-2k (it was long time ago), had my front windscreen tore once (due to JPJ inspection), and was warranted with new tint by the shop. After so many years, the tint has faded, reduce to 80-90% VLT. Nevertheless, it still reject heat quite well. Not as good as new, but definitely better than bare. Take about 15 minutes to properly cool the car under hot sun, and I can still drive at noon with half air-conditioning without feeling uncomfortable.

Anyway, I came across and visited Huper Optik and Raytech tint shop recently, surprise to find their shop to be quite close to one another. Here's my observation, purely opinion, for the price of ~RM2k:

Huper Optik
Side/Rear: C50S (security tint) / C50 (non-security tint, on paper slightly better heat rejection than C50)
Front: C70 (non-security tint, comply to JPJ) / Sech60 (non-security tint, slightly darker than C70)
Either combination is warranted by the company in case of fail JPJ inspection.

Another option is C40, which I find this to reject heat better than C50S/C50. This tint is slightly darker, not a security tint, and was not warrant by the company. I was quoted same price for both combination (C50S and C40).


Raytech
Side/Rear: CS85 (Security tint)
Front: V97 (non-security tint) / UL70 (non-security tint, upgrade)

There is another version, CS75 (many people ask about). I find the heat rejection is not as good, and not worth the saving from CS85.

I also came across some reader say V97 is a bit dark for driving at night, and the spec sheet did show slightly darker VLT than JPJ requirement. (I didn't notice the spec till I get back, so did not ask about the warranty with JPJ). UL70 seem to meet JPJ requirement, I guess that's why it is there as an upgradable option.

3M
I didn't visit their tint shop, but I got a chance to visit 3M Innovation Center near Shah Alam to see some of their products, including their tint. 3M tint is proven to have very good IRR, and they seem really proud of it (block out smartag).

One of my friend has 3M tint install on his car, he say the tint work really well and better out his previous tint (some local brand). To prevent the smartag issue, he reserve the top part of his car (where the dark tint normally is) for different brand of tint that do not has issue with smartag.

Llumar
I didn't visit their shop either, but worth mention as another friend of mine has it for 3 years now, and the tint is still as good since day 1. Only thing is there are quite a lot of fake Llumar in the market (so I have read), which is good cause it means the brand is growing and proven, just that consumer need to be more careful at selecting tintshop.

V-Kool
None of my friend has this. Not a very popular tint nowadays?

For those that like to know how does a car feel like without tint and have problem to access to a car without tint (for comparison sake with your newly apply tint), try getting into a parked taxi at noon and take a ride with it.