There Is Some Rubbish Out There
Bolts and nuts that sink into mush if they've had to come out twice before. Poor photos, even poor digital graphics (instead of proper photos), no close-ups, no indications of steel gauge (often) and in forums, "I have the XYZ rack from ABC. It's shit. It's too light so every time u rack a weight it slides around. So I bolted it too the floor. Because I did that the frame twisted over time." One person used his safeties as pull-up handles for inverted rows, and they bent after a while. So much for safety when a loaded bar drops on them.
Racks like that are made cheap to be cheap, by contract manufacturers for a supplier who hypes it up and makes it always-on-sale.
Just as important for practical strength is how corners of a rack are built. Here's a diagram from a manual of feeble rack on the left (about which there's much supplier hype about "setting industry standards" and laser-cutting this-and-that)
On the right is a Powertec corner.
On the left, they cut bits out of the upright and slide it onto the base. (Cheap to make) On right, the Powertec unit. It's actually better for some things you can't see.
Not only does it have backing plates. Not only does it have a lot more bolts, the bolts are bigger. (Most manufacturers in this market use metric M10's, (10 mm). Powertec uses half inch bolts, much bigger in diameter. Powertec structure uses 5 mm steel - but better than that, there's a welded sleeve you can't see on the bottom piece, that the vertical structure slides over and through which the big bolts go. So, they go through the vertical wall, the sleeve, the base and the backing plates. Lots of steel. Many times the strength if you were to calculate it, even that of others that do have backing plates. And this is cold-rolled steel, more expensive, but provides more strength than equivalent, only-hot-rolled steel. (And permits a better coated finish by far) Note: some others do have backing plates, but not the sleeve's extra 10 mm, nor the other features there. And with many lower-end racks, they simply don't have many bolts! (Great!) If you look at the other aspects - J-hooks, safeties, how chin up bars are attached, options....the cheap story is the same, of course.
The picture at the bottom shows the 5 mm of the standard Powertec structure; photos courtesy of SamsFitness, Australia.
You might pay a bit more for Powertec. Even if you don't want to get deep into the 100's of kg lifts, it's a lot more pleasure to use. It's why we've found them faultless to date, and many of our customers have had racks before and know what matters.
Three-sided sleeve - left hand side visible - into which backing plates get bolted, as well as uprights.