Spot on @JoshHMostly build quality over all,
Are all the panes of glass square?
Silicone nice and even with very little to no bubbles in it?
Silicone is applied clean and tightly on inside edges of glass
Are all edges of the glass polished smooth and clean?
Any holes are drilled neatly with little to no breakout on the edges
Return and overflow holes are drilled to spec?
If internal overflow, is it siliconed properly to the tank?
Is it made to the right specs and located properly?
Any additional bracing/corner reinforcement is applied cleanly