For years I made my own sweet thai chili sauce. I could vary the heat and frankly thought it tasted better than most I’ve had. That said I’ve come across the Mae Ploy brand sauce – bought some and tried it. I now always keep a bottle on hand and interchange it for freshly made as time permits.
I will note that I settled on Mae Ploy after buying some other that was (even for my heat savvy tongue) too hot. My home has eaters with varying heat tolerance so this one is a good starter/base to which I’ll add Sambal Olek or Sriracha.
Every grocery store I’ve been in over the last few years will carry some brand of Sweet Chili Sauce – in my opinion it’s worth seeking out the Mae Ploy – try your local asian market or talk nicely to your grocer (or order online)