I don't want to touch that on this forum. People on here have definite opinions about what they perceive as the 'best and only possible solution to tie down's.
I'll venture my opionion (only) because I'll probably get slammed for it anyway.
I use HappiJac tie downs. The reason why is because I primarily run my PopUp TC off the road, on fire roads and seasonal access trails so I need a higher mounted tie down assembly to clear things on the trail like rocks and logs that might be along side the narrow roads and trails I run on.
If I was on pavement or staying in campgrounds with no low obstacles, I'd run TorkLift mounts but I don't, so I don't
One thing to keep in mind is, you won't have the high Cg associated with a hardside. Hardside campers tend to 'roll' back and forth on uneven terrain and on curvy roads because the vertical Cg is much higher than a pop up. On a hardside, heavy appliances are mounted high (microwaves, entertainment centers and the solid roof and ac unit and they all add to the rocking effect. You don't have that with a pop up. Everything is mounted lower and the roof is also lower.
I've run HJ's for years, first on my Lance and now on my pop up and never any issue other than replacing the turnbuckles because the old ones rusted away.
You catch a frame mounted Fast Gun on a rock or log on the trail, it could have very serious implications to your truck frame and/or the sheet metal.
Just my opinion and what I use.