www.sensoft.ca is the only one I can personally recommend. I'm sure there are many other great GPR brands out there but this is the only one that I have invested in. They have great live in-person mini courses offered around the U.S. and world. Covid has affected the amount of live classes but there are still a handful offered in 2022 in various locations. They also offer online courses and have GPR rentals as well as rent-to-own options as well. And like any great company, awesome customer support to boot.