I’m going to throw a different point of view out there based on my personal experiences and observations.
Disclaimer I am NOT a Physicist OR Engineer 
As most of you have seen in my posts my OF utilizes a flip table with a single 2"x4" for legs in the base and 2 fold down legs that do not even lock open (gravity does that work for me). While I do utilize a very stiff torsion box for my deck, the rest of my machine stand, while sturdy can be flexed, leaned and sways during carves as it desires.
I have absolutely zero issues with repeat zeroing, accuracy, cut quality, and overall machine performance… I even left my 1.0.6 Jerk rates at the 20K the BETA firmware shipped with. I can tell you that each depth of cut is clean, concise and nearly non-discernable and a quick hit of 220 grit makes it smooth as a baby’s bottom.
My machine sways slightly on full speed direction changes and smoothly sways back. I will say I have 1" clearance around the machine to accommodate this motion. If it were knocking into a wall or other table on that sway my opinion would be completely different as that slam could likely cause issues and skipping.
The Theory:
The Facts:
- The OF is rigid and stiff as Hercules
- The OF is securely screwed to the table top
- The Table Top is (see #1)
- The workpiece is securely clamped and fastened to the Table Top
The Hypothesis:
A body in motion stays in motion unless acted upon by an opposing force. If you have removed the ability to slam into a wall or cabinet, then inertial is slowed by the opposing forces introduced by the woods’ natural desire to remain in its shape. These forces “slowly” (key point) counteract each other and bring the sway to a controlled smooth stop then back slightly in the opposing direction, with the OF and its payload all secured to the platform that movement is aligned and harmonious… Thus yielding clean milling results.
(sorry this is what happens when I have have an extra cup of coffee in the morning… lol)
I totally get as an arbiter of the “Brick $#!+ House” Principal the desire to build everything as strong/flat/level/rigid as humanly possible. I am a guy that built his BBQ Island out of 14 gauge steel studs which only holds a 72lb Blaze BBQ, I do get it!
The reason I’m posting this more than anything is I want to share with (more the newbies) that yes a lot of these mods are absolutely amazing, and inspiring there is nothing wrong with bolting your OF down to a piece of 1" MDF on a 2x4 built work stand and have amazing cuts & carves. I do not in any way, slight or dismiss those who have gone above and beyond… conversely I admire it. But… you can have a happy CNC life simply out of the box.
Speaking of Box… I’ll get off mine made of Soap. 
Hope that helps, makes you smile, and encourages your CNC journey wherever that may lead.
-Alex