I had other neoprene straps over the years, so I decided to buy the Mono's take. Everything's good with my 4.0 Solostrap Neo, but I wanted a narrower width and more ventilation (Solostrap can get hot). I also owned a 2.5 SoloStrap, but my 4.6-4.8 kg basses need a thicker strap.
I've made several attempts to like it, but I seem to hate this strap every time. Metal buckles that beat your instrument -- check. Length slipping off in unexpected moments -- check. Unstable construction that slips when you shift the instrument -- check, try shifting the neck and you'll hear and feel the buckles slipping. Weird industrial look with a huge screaming logo -- check.
In fact, I could live with all those if the strap was comfortable. For me it's not, it's cutting into my shoulder worse than a plain narrow nylon strap, ten minutes and I'm done. Maybe my instruments are heavier than the strap expects, IDK, but my other neoprene straps are much better. I've also tried a lighter instrument, my Strat is just 4kg and Solostrap Neo 2.5 works good on it. A wider Mono doesn't and gives me a shoulder pain.
My recommendation: don't waste your money on this strap. Get a Minotaur for half the price. Or the D'Addario Poly for a fraction of the price. Or get a Solostrap Neo if you want neoprene. They all are worth their money, but not the Mono strap.