I was like you in the beginning... I did tons of research myself and ended up here, there and a few other places.
My suggestion would be a US vendor first to get your feet wet. Skye, Nexaph... whatever your research/reading made you feel comfortable with. The one I bought from is no longer in business. These are the chances you take. Then keep reading and following to see what CN vendor you would make your first purchase from. Are you comfortable with paying in crypto? Paypal? Zelle? Bank wire transfer? Those would be factors as well.
Just because there are all these huge "sales" and "promos" going on right now I am still waiting... because I don't know if tirz is working for me and I don't want to be stuck with 300mg. Granted, I am sure I could sell it but I am just not comfortable buying right now.
I have also bought GLOW and Cagri from a US vendor, way overpriced, but I was not ready to buy a whole kit if I didn't like it or it is not doing anything for me. I guess what I am saying is you have to gauge where you are at and what you are willing to do.