I agree there are other advantages. But at the risk of offending some, I'll play devil's advocate.
Like people, some deer are just stupid. I've had similar situations to yours play out sitting on the ground, paddling a canoe, and sitting in traditional stands. It is true that the profile of a saddlehunter is different, but I've been picked off a tree in a saddle. Saddles also require more movement for certain shot options than a tree stand. Going up-and -over the bridge for example is a LOT of movement. Movement will get you picked off.
I look at it this way. I have a Browning Citori I squirrel hunt with. I very much enjoy this gun, and believe it is the perfect squirrel killing gun. It carries well, patterns well, and allows me to quickly switch between chokes for different situations. These are undeniable advantages over, say, an 870. I can squirrel hunt every day of the season should I choose to do so, and I usually do. I had the money, and I bought THE BEST. Bully for me.
But, I would not for a second recommend that somebody financially inconvenience themselves and purchase a citori just to hunt squirrels once or twice a year. The advantages are NOT worth the extra money for most folks.
If OP wants a saddle, and can find a saddle system for a price that fits his budget, then that's awesome. There's plenty of folks here to help him with that, myself included. I just wanted to point out that there was no reason to feel like he was "settling" by purchasing an XOP.
I can really appreciate this post, much like you nutter when I buy something, no matter what it may be, it's generally going to serve a specific purpose, and I want to buy the best there is to give me the biggest advantage and best user experience possible. I'm a massive believer in the "buy once, cry once" mantra. Sure I can get some cheap rope and make myself a cheap linemen's belt, but I love the advantages of the factory spliced rope that Tethrd offers, and the ease of use the ropeman 1 provides going up and down a tree. Are those necessary? Absolutely not but I know they provide an edge over the alternative and I also know that I would eventually give in and pay additional money to upgrade to them anyway ... might as well just start where I want to be in the end, right?
I just ordered the XOP Vanish and Helium sticks, really can't beat $100 for 3 sticks that come in at 8.4lbs (plus straps I imagine). With an aider or two I should be able to get plenty high in them. I didn't get the Vanish because I decided on going with a hang-on, that debate continues. It's just that the Vanish is the same price as the TETHRD platform but I can hang it in a tree right away and use it as is until I decide on the saddle ... and with the Mantis production still being a couple weeks out at least I should have some time to get some seat time in the Vanish which will likely help make my decision. We'll see! I also just ordered the TETHRD linemen's rope and a Ropeman 1 so I have everything needed now to get up the Heliums and get the Vanish hung.
In the end I think this is the best approach as it gets me going and practicing by this weekend. I have a very strong suspicion that I'll end up in the Mantis (probably much sooner than later) and if / when that happens I'll simply steal the Vanish seat and build my platform out of that and be off to the races.
Still interested in hearing more opinions though so keep them coming, and thanks to everyone who's commented so far!