I'll begin with what I needed:
Something sturdy enough, and large enough to handle my XL framed 26x2.5" tire wearing bullit. I also wanted something absolutely stable and built solidly. I did not care about weight. I also wanted something that could fold up tidy when not in use.

I know the thread title is for the rack I ended up with, but I'll begin with a comparison to my buddies Thule 990xt-

I tried my friends thule 2 bike platform rack -

-Easy to fold up and down once the top bar was out of the way
-Quick and easy to load the bikes once the wheelbase is set on the cups, easy to adjust the wheelbase
-Easy to lockdown the arms and lock them - however the locks they use are extremely cheap and look stupid easy to defeat
-The tires on my bike -BARELY- fit inside the retaining *plastic* ratchet straps - in fact the first time we used his rack with my bike, about a block from my house my bike's front wheel jumped out of the rack and my bike ended up dragging on the ground for about 1/2 block before we realized it happened So now I have a flat spot on the end of the handlebar/grip and a gnarly flat spot on the front tire...but alas Santa Cruz bikes are tough as hell so nothing really got hurt
-Rotating the top retainer bar from verticle to horizontal cannot be done 1 handed despite there being a nice plastic lever there, the bolt that locks into a slot to hold it in each spot gets totally wedged and stuck in place wherever it was left, really poor design IMO.
-The rack uses a 1.25" hitch to 2" adapter to fit in most hitches, and the adapter is way too small, and even with the "threaded hitch pin lock" the whole bike rack can sway side to side what looks like a foot from the drivers seat but is probably 3-6" in either direction at the edge of the rack...really sketchy looking!

So onto something different, but still on a similar budget, I picked up the HR1400 for $390 from amazon, 2 day prime shipped for free.
It arrived today so I went home for lunch and slapped it together, here's some pictures -

My bike fits quite easily and I threw it into what I felt would be the most difficult to load spot and I still had everything tightened up and ready to drive away in under a minute.
-Rather than cheap plastic ratchet straps to retain the wheels/tires this rack uses a simple and effective velcro strap - I feel much more confident that my wheels won't be popping out of this rack!
-I still have some adjustment to play with as I want to have the top hold down bar hitting near the seat tube so it's on a flat bar of the bike, but it felt really secure even like it is pictured here.

The rack is so stable and secure because of this system pictured - It uses a standard hitch lock at the hitch, but there's a rod that the pin goes through in the middle which is grabbed by this crank pictured, once the pin is in you turn the crank to add tension to it and that's it, locked down tight solidly mounted to the truck!

The 4 bike add-on portion of the rack attached to the front 2 bike portion in a similar fashion with a hitch pin and tensioned rod on a crank so it too is very tight, I did notice this section does feel not quite as solid as the first 2 bike part, but still tight. Of note this portion inserts with what looks like a 1.5" hitch size as it's too small to put directly into a 2" hitch (I tried throwing this part on the hitch of my other truck and no dice, would have been cool to effectively get 2x 2 bike racks for $400 oh well)

It can be folded 2 different ways, here's the most compact way for when on the truck, the other way I didn't remember to take a picture of but it's how I have the 4 bike add-on portion stored in the garage for now - you can leave the vertical hold down portion vertical and the arms holding the wheel pockets can be folded vertical, I was able to slip it between my work bench and freezer in my garage no problem, it's about 6" wide by 2' deep folder up that way and stands on the hitch bar by itself.
It uses hitch pins with retaining clips for all of the folding functions (including tilting down and away from the truck in case you need to get into the back window for something), while not as nice as the plastic pull tabs of the thule at first glance, I feel they will be 100% more reliable in the long run.

It included 4 keys, and a locking hitch pin + a ~10' cable lock that are keyed the same, while not as convenient to lock the bikes as the locking hold down arms of the thule, this at least looks a bit harder to defeat for the average lock picker, and at least looks annoying enough to defeat that I would feel fine parking at a place after a ride to grab something to eat.

So for someone looking for a 2/4 bike platform hitch for bikes of any size that is super stable I would definitely recommend this.