I have owned the Gura Gear Unita for about 2 months now and I can say that I really like the bag. Besides buying the bag, I also own the Medium Pro Module as well as the Small Pro Module.
The bag seems to be well made, and has a very comfortable fit on my back. Honestly, even though the bag currently weighs 17 pounds with my gear inside (6D, 17-40 F4, 24-105 F4, 100mm Macro F2.8L, ND + Grad ND Filters, extra batteries, cleaning equipment, et cetera) it doesn't feel like it weighs 17 pounds on my back. I like the fact that I can open the backpack from the front / back to access my equipment, and that both modules are removable. I really like the fact that the bag comes with a rain cover (although I haven't tested the rain cover yet).
The front compartment has an opening big enough for a jacket, or a sweatshirt, plus pockets for a wallet, keys, et cetera and I do believe that is a big advantage for the small accessories instead of them falling down in the bottom of the bag.
Another positive is the ability to use just one module for camera gear, and to take the other module out and use it for hiking equipment, et cetera. I find that a real plus.
What can be better:
I have noticed that without the Small Pro Module inside the lower compartment, that the Medium Pro Module seems to slide down and down. The straps that are suppose to hold the Module seem to slide down, because the strap goes through a holder and then Velcros to the side of the module. I noticed that one day, the module was taking up 50% of the lower compartment where the small module goes(Even though I didn't have the other one in). Honestly, I would've liked to see a wall in between the two modules, when the bigger module is on top, thus not having the module slowly go towards the bottom of the back and having that space for clothing, food, et cetera.
Also, the straps that hold the two modules in place aren't easy to pull through the strap holder because of the amount of space between the module.
I will also point out that putting two modules inside the bag is really tight even though both do it.
One last thing I wish they would've done is to change the inside color of the modules. They are black and it would've been better in my opinion to go with a light grey. It looks too dark inside even with my Canon lenses.
One last thing that Gura Gear could've done better is the shape of the Modules, not having them as a rounded shape, but a more square shape to put lenses in the corner.
I would've liked to see a more dedicated Hydration system instead of attaching it to the front of the backpack. I read the reviews on the Tripod Hydration System and it seemed like a bad idea.
Overall, I really like the bag and the modules. The bag is $199.95 not including the modules which can add up to $159.90 (Medium $89.95 + Small $69.95). I would've liked to see a more reasonable price, say for example $300, maybe up to $330 and included a dedicated hydration bladder. I would've paid up to $350 if they had the hydration system somewhere inside the backpack instead of putting it in the very front of the bag. This backpack will really suit me as a hiking backpack and I cant wait to take it to Mt. Rainier this coming Spring and Summer.