I had the cabinet for the tankstick from rec room masters, and it was functional and simple. Compared to what you could build, it was no nearly as substantial feeling (a little light, not exactly flimsy but not exactly sturdy feeling either). The bezel is basically a thin sheet of plexi and probably the thing I disliked the most. I had the regular sized, not the XL, and you could use any flat screen monitor that was 22.5 inches wide or less. I was able to shoehorn a Dell 23" lcd in it with zero clearance on each side (exactly 22.5 inches wide). It used a standard VESA mount for the screen.
I am 5'10" tall and I found the cabinet to be just a little too short for me. The controls ended up being about 2 inches lower than was comfortable for me, but I couldn't say how that compares to original cabinets, the last time I was at an actual arcade I was shorter, lol.
The XL is only wider than the standard. For purposes of modularity, if you used the tankstick as a basis for building other controls then it would not be a bad solution, it is already basically modular.
But because of this, it doesn't look like it was really built to be one unit, the tankstick doesn't exactly fit well in the cab. The retention mechanism is just rubber feet on the bottom of the unit fitting into a couple holes in the cabinet. So if you are looking for something that is reminiscent of an arcade cab, the rec room masters cabinets work. If you are looking for something that could be found in an arcade in 1982, build your own.