I often wonder why Humbrol seems to be a taboo brand, I v'e used there enamels for years without problems, there thinner is so so but at least it doesn't smell bad but I use enamel thinner from the hardware and its great with it. There Clear I'm sure is Future floor polish I'm sure you have read about and decalfix is the friendliest decal solution going. I wish they would use jars instead of tins but they keep the paint for years so nothing wrong with them.
It comes down to that age old question of which is best, short answer is what you like and are comfy with. Every person has a unique situation and its what suits, smell is a issue if your in a house but not if your in a shed for example, drying times etc.
There's endless threads on here and other forums about whats best but its really what you like to use that's best. I.m sure there will be many more opinions to follow.
Hope that helps. Good luck.