The Miflex XT Tech hoses look like they were developed to address 2 complaints by divers who prefer a long hose setup:
1. The long hose setup (5ft/7ft long hose is routed across the chest and around the back of the neck and around to the mouth. The braided cover of Mi-flex hoses was often found to be uncomfortable due to the way it abraded on some folk neck or abraded on their exposure suit/neck seal.
2. The standard Mi-flex hose was positively buoyant and would have a tendency to float, halo-like, above or around the diver.
The XT Tech hoses have a smooth outer polyurethane layer to address the abrasion issue. It has kevlar reinforcement around the inner braid, and however done it is supposedly no longer positively buoyant.
You will find the some eschew Mi-flex hoses in favor of rubber hoses. There are strong opinions against them due to early issues with their high-pressure hoses, and the breakdown of the actual air-hose inside the braided outer hose, along with the two issues I noted above. The issues with the standard Mi-Flex hoses have been worked out some time ago and no longer seem to be an issue. The other two issues are addressed with the advent of the XT Tech hoses.
The common argument that is often given against mi-flex type hoses is that they have a limited life-span of roughly 5-years according to the manufacturer....the claim often made by folks who make this argument is that they have been using standard rubber hoses in excess of 5 years without issue. If one were to look at manufacturer and retailer recommendations for any scuba hose, the recommendation is to replace at around the 5-year mark....whether one does or not is a personal decision, but manufacturers apparently do not expect their hoses, regardless of material they are made from, should be replaced at a specific interval...for "safety".
If the hoses have features that you want/need for the type of diving you do, at the price you wish to pay, then all is good.
I personally have mi-flex hoses on my reg sets and have yet to have a problem with them. I like how the flexibility of the hose lends itself to tightly coil my hoses when stored for transport (I dive with a 7ft hose).
The 360 swivel for the octo on the short hose is superfluous, you can save money here if you have not purchased it yet.
-Z