I'm not going to try and convince you wether or not to keep your order, but I can tell you what I like about the Max vs my 7 Plus and then explain why I'm upgrading.
I've been looking forward to an OLED iPhone for years, and when it finally came out last year I was underwhelmed by the form factor, technology and other 'advancements'. Sure, it was redesign, but it didn't speak to me, especially the 64GB for $1k. The Plus phone still did more than the X, namely landscape mode. Instead, I opted to sell my slow 6s Plus (which I later found out was due to the battery, thanks Apple!) and upgrade to a used iPhone 7 Plus. I'm a technical nerd, and I love spec sheets, but I was more excited when the red iPhone (a color I had wanted for years) was released.
This year, I liked the new phone. I loved the bigger screen, I loved the better camera, but it's odd as it's not a real 'S' upgrade IMO. The S phones have taken huge steps in processing power: 3GS introduced the first new CPU, iPhone 4s added dual core CPUs, iPhone 5s brought 64-bit, iPhone 6s increased the clock speed, GPU, efficiency and RAM, but then iPhone 7 brought more cores and RAM (Plus), and iPhone 8/X brought even more RAM and cores, better GPUs and more. The iPhone Xs and the A12 had nothing left to give. Sure, it's 7nm which is groundbreaking, but the performance increase and power decrease don't look to be as great as thought. The Neural Engine is great, but the on-the-fly CPU isn't any better.
The only reason I am upgrading is because my father was dead set on it. Had it not been for him getting his Xs Max, I wouldn't have received $700 off the purchase from Verizon. I refuse to pay $1k+ for a smart phone, instead I was going to buy used like my iPhone 7 Plus, but the $700 off was too good to refuse. Originally I was going to get the 8 Plus on sale, but I know I'm going to keep this new phone for 3-4 years, and for less than half the price. I couldn't beat it.
I can comfortably say that had it not been for the $700 BOGO deal Verizon has, I would not have upgraded.