I started out with a handheld thermal first then got my rifle mounted thermals.
Imo you need a handheld to go with the rifle. Way easier to scan with than trying to use the rifle and your arms getting tired. Plus I've used it ,handheld, tracking a wounded animal in the dark that I wouldn't have found without it.
Ive got Pulsars and have had really good luck with them.
Have had 2 handheld and 2 scopes.
Got my first one in 2017 and they have came a long way.
Smaller and lighter.
I haven't had any other brand so cant help ya there.
You'll like them when you get one.