Just that I recalled seeing your posts on the GL.iNet board recently!
From what I've seen GL.iNet keeps their firmware reasonably current with OpenWrt and their changes are primarily additive -- NAND support for their specific devices, for example, or the set of packages that provide the GL.iNet "experience" (with the usual LuCI interface available as "Advanced").
Their choice of providing a U-Boot version with browser access is a good example of their approach to things; make it easy for end users. If you've got knowledge of electronics design and fabrication, when you open their units you can that while they are inexpensive, they aren't cheap on the inside, just well-designed with a specific price point in mind.
At least in my opinion, the GL.iNet firmware provides some great functionality for many users, especially in travel / repeater situations. I've got two AR750S ("Slate") units and one of them runs a development version of OpenWrt, the other, stock GL.iNet firmware. As much as I'm a command-line guy, when I'm on the road, the robust simplicity of the GL.iNet interface is an advantage.