Big companies are not necessarily good. I heard that many projects are subcontracted to outside engineering teams; Guerrillas are not at ease, for fear that if something goes wrong, they can't find anyone.
After all, we are not professionals, and this industry is very irregular.
My brother just started decorating last month, and found a merchant on Love Decoration Online.
It is said that you can get an unconditional refund if you are not satisfied there, and there is a third-party deposit, which is more secure.
I suggest you get to know it.