I currently run a NOX 35 as a handheld scanner and IMO for a handheld its the best on the market, period. Has plenty of FOV as well as a good base mag and the best image quality in the industry, plus its Murica made!
I am retired and hunt as much or more than anyone so my stuff gets put through the ringer in about 6-7 different states in extreme cold in NW Montana to hot humid nights in Southern Indiana, Kentucky and Illinois.
The 18650s are awesome and I can hunt all night from sundown to sun up in subzero temps on 4 batteries. In 30ish degrees I use about 3.
The best way to run a handheld is with a chest rig like the Eberlestock recon, Alaskan Guide Denali etc. and have it tethered to the rig. When a coyote comes in simply put the scanner in the main compartment and get on the gun. Some guys also use a selfie stick to combat arm fatigue and its a little warmer keeping your arms close to your core not elevated.
As for a helmet mounted scanner, it has advantages like being hands free, larger FOV but it also has disadvantages also. HMTs need to be light and small and those size units are 1x so you have a larger FOV but the detection range is FAR less than the NOX 35. Another disadvantage is in extreme cold weather its kinda hard to get a helmet to fit good over heavy winter headgear. Also a HMT is a far more expensive setup.
I do agree that a person in warm/temperate climates that spot and stalk or drive ATVs while hunting that the HMT setup is the bomb and a better option but for a stationary coyote caller like myself I think the handheld is a better option.