Unless you are going to be completely stationary, I MUCH prefer a helmet mounted device.
I experimented with a bunch of different setups early on and I believe it has the fewest drawbacks. The ahaa moment came when the aforementioned former Delta/CAG member illustrated how you could run helmet mounted and still use a standard Eotech, RMR, Aimpoint, and even some magnified optics like an ACOG with the device on i your noggin. Your position might feel a little wonky at first, but once you realize you can score hits out to a couple hundred yards it starts to make sense, because it always on your head, it is always on, you’re not trying to sight down a rifle to employ your device, you can run the same rifle day and night without fumbling around with anything, and you can transition to your pistol without drama. A laser/illuminator in this configuration also opens up a lot of options.
If I’m sitting in a blind scouting for hogs, by all means, I would take the rifle mounted thermal, but in any situation where I’m moving it is intensifier on the noggin for me.