This will be the only power rack I own. Not because it's the industry best, but because it's good enough for me to never need to upgrade, and instead spend money on attachments and weight and things I care more about. I'm glad I went with a 3"x3" (actually 75mm x 75mm) with 5/8" hardware (actually 16mm AKA M16). Once you know the actual specs, you can adjust accordingly. Two rep cave is a great resource to see what your rack is compatible with, and the X-3 is compatible with Rep's PR4000, Griffin's GR3 Lite, and Vulcan's nobody cares. Having access to Titan's sales and Rep's quality with free shipping either way makes this a great eco-system to be in. The 5/8" is annoying for leg rollers, and I can't use my Mutant Metals handles on my rack, but unless you care a lot about leg rollers and handles anywhere on your rack, this is the way to go. Get the 90" tall if you have the height in your space.
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Build Quality