The hinge is fine. The locking mechanism is poor in my opinion. Needs a vape band if you plan to pocket it.
Or a side-by-side mod
I haven't had any problems with the Nano so far, but I must admit I see the full size version as my relaxing-at-home-tank. Partly because of the hinging top but also because it sits freaking high on my mod! It tips over much quicker then with the Toptank for example.
Got it on my iStick 30W for now, but I'm thinking it will be perfect for my Pico (wish I could find some o-rings for the Nano to match the pink Pico). Still haven't gotten around to trying out TC, but now I can play with it.