I owned alot of backpacks in my life.
Huge 100l+ hiking ones, "tactical" ones, "urban" ones, or just random backpacks. 5.11, TT, Tatonka, DA, XDD, etc etc etc. FT one is definitely one of the nicest i tried.
This one definitely won't fit carry-on luggage but i bought it for my train and car trips where carry-on limits is not a problem.
This backpack is over-engineered for sure. Amount of small details is truly astonishing. Everything, absolutely everything in this backpack is well-thought and designed to be as useful as possible.
It's also absurdly HUGE inside. You can't really tell how much stuff you can shove into it until you tried. I put 1-person tent, spare boots, sleeping bag, and some clothing for a week trip as well, and i can probably fit twice as much (except boots, they're just too big). And i hasn't even touched other pockets, it's all in main compartment. And if you don't carry so much stuff ATM, backpack can be nicely compressed to much lower profile.
Had no issues putting my M sized first spear plate carrier, helmet and belt as well. Can probably fit it together with my hiking/camping stuff if i needed it.
Waist belt is definitely a must for this backpack if you intend to carry heavy stuff, but if you carry big-volume but light stuff you can probably skip it. I store mine in "hook and hang thru" compartment when not in use. It's very easy to attach / detach and i use it only when needed.
CCW pocket is big, and if you don't CCW, you can easily store a tablet or even small ultrabook there. It's pretty well protected.
Outer pocket have well-done organizer, you can easily stash your multitool, pencil, batteries, notepad, powerbank, medical stuff, etc small items with good organization and easy access.
The back padding is very, very nice. Hasn't really noticed any significant sweating on the back like with some other backpacks. It's wide, big, and generous. I have a rather slim build (186 cm, 80 kilos) and padding is still very comfy.
Absolutely love the modularity, too, since waist belt and hook and hang thru stuff can be used on all of their backpacks. Might as well get another one from FT, smaller one for daily usage or light trips to range.
The molle ("soft" one, like the one you can find on first spear's plate carrier cummerbunds) on the back of main compartment is a nice touch, definitely love the concept. I personally have no real use for it, but i see how it can be used in different scenarios.
Also, finally backpack that have glasses pocket on top and not on front like many manufacturers do for some reason.
Sternum strap can easily be adjusted up and down, it's also very stiff so it won't slide on it's own.
Spacious molle on straps means you can easily fit radio and/or GPS on it.
Molle loops on top and bottom of backpack can be used to attach your tent / sleeping back / sleeping mat.
Carry handles on sides is a nice touch too, definitely more comfortable to carry than with top one.
Overall, small details is what is great about this backpack. It's like someone thought "what if i can fit every single feature found on different backpacks into one ultimate backpack". And hell, it works. And works good. I will use it for my (relatively short) hiking trips, train rides to other cities, range trips and other stuff.
P.S. To First Tactical - please add international shipping. I'm sure people will appreciate it.