Arguably my shop has produced some of the most aggressive cart builds that have ever been attempted. I have been very fortunate in that over the years I have had an unprecedented level of exposure to many very successful sound mixers who all have their workflow and preferred brands recorders and wireless.
I am pretty much on the same page with @joepfeil. Early on in my career I used a mixture of prosumer wireless systems and some second hand professional gear. I was also using a Tascam HSp82 at the time which had toggleable inputs as either analog or AES. Long ago when I first looked at the Zaxcom website I was blown away with how complicated it all seemed (I was very green). I was homeless at the time and living in an Astro van. I ended up dropping my entire savings into a RX12, Bluefins, a couple ZMT3's, and a 743. It was an unfathomable investment for me at the time considering my living situation. I did it because it was an investment into myself and my career.
I will never forget the first day I used the 743 on set. It was for a Tove Lo music video. My little makeshift soundcart was at the back of the stage and I was so scared that I was going to be plagued with the same RF problems I had suffered though with the prosumer gear for so long. Not only that, I had just wired in and powered up the RX12 for the first time just days before the shoot. I was working by myself and running back and forth between the cart every time they rolled. The signal was clean, rock solid, and for the first time I experienced true professional confidence in both myself and my equipment.
Fast forward many years later and my inventory of Zaxcom wireless systems and recorders has grown significantly. I credit much of my professional success to Zaxcom.