I used plenty of Quectel modules after testing many other brands in the past 15 years which includes SIMCOM, Cinterion, Sierra Wireless, and uBlox. I even prototype few other less known brands (some which already disappear). I think is probably the best in terms of balance between price and quality+support. I bought the modules from a mix bags of China distributor (which actually they are not supposed to sell to outside of China) and also directly from Quectel. I think Quectel's support is okay as long as you buy from legit channel. They will help you and figure out what goes wrong even for units already deployed out there even all the way to checking their server (I used their Quectel Location services). Documentation is also very good and excellent. Even before I was buying directly from them, there was an instance I was desperately needing the certification test results documents (not just the certificate) and they obliged to help. From there onward, I balanced the purchase ratio and split among them depending on the urgency just a token of appreciation. I really like Sierra Wireless modules but their packaging have a very bad yield during assembly. At first, I thought it was just me not doing a correct design but when I hear from my regular PCBA factory mentioning that even their customer that uses Sierra Wireless have a very low yield. Other than that, I think uBlox have a nice product line-up that maker likes due to it's slim form factor that fits into a *bread boardable* development board but they rarely have global band and they not cheap to begin with. SIMCOM on the other hand, it's a brand that if you are willing to work hard and get your hands dirty, it can be quite rewarding due to the fact their module is among the cheapest around and not too bad in terms of specification. Documentation wise, they are among the worst though.