Respectively:
There is a huge difference internally from XOJet, other "branded" providers, and NJA. There are many alternatives out there some charter companies charge the same price for a GV that NJA charges for a Sovereign. Price in aviation should be taken with a grain of salt.
Not saying that XOJet or other "branded" flyers are not safe, but are they converting their pilot training to part 121 (airline standards), Well, no. XOJET converted to 121 standards years ago. do they have an Aviation Safety Action Program (ASAP) that allows pilots and workers to write up safety concern that is reviewed by the FAA and company so changes and training can take place, ASAP yes, Check. do "branded" flyers have FAA award winning maintenance programs, FAA Award Wining best practices awards, Yes. do charter companies and other fractionals have a half dozen FAA inspectors permanently on site to review every move we make (just like the airlines...you would be lucky if an FAA inspector showed up once in a while to a charter company to review what they really do), 6 is a large number. There must be a past reason for that degree of FAA scrutinization. and do they have work rules in place that protect a pilots rest and duty periods? Yes These are just a few safety items that seperate us from the "brands". How so?
Can you get that branded plane when you need it? Yes, there are guaranteed availability programs offered at a higher cost, but still considerably cheaper than ahem "other" providers. Can you upsize and downsize? Can you go where you want when you want? Yes, of course within safety limitations. Are you sure those charter pilots are both properly typed in the aircraft? Yes. Are they flying a broken plane that should be grounded and are doing so to jeopardize your safety to collect your money. NO Never! At NJA we value your safety, ground the plane, and historically, within 60 minutes, you're on your way again on a new tail. Can "branded" flying do this? Netjet's does not guarantee recovery flights in 60 min. Once your company is right sized, recovery times will go up.
Yes XOJet is cheaper, but as stated, they can tell you if they are or are not going to take a flight. Not if you choose a guaranteed program which is still much cheaper, and if it is a low volume day, you still qualify for the cheapest flight on that day. They also tell you what airport is better to go to that is more convenient to the company. Information is power. You can choose the cheaper option, or any airport you like. Are they cheaper because they are taking high time worn out NJA sold aircraft (their Hawker 800s and some Xs), strapping new engines on them and pushing them hard...you bet. I always thought that was a poor decision at least from a marketing perspective. However, XOJET's fleet in total is still much, much younger than NJA's.
Charter companies at time can be compared to the old ValuJet airlines. They take old planes, strap on new engines, charge under cutting prices, place some duck tape here and there to keep moving, push their pilots beyond exhaustion (or they could be fired for not taking a flight), and from the outside all looks until something happens. And the news is full of "something happening".
You can compare, air taxi, charter, and private accident rates and then compare them to fractional flying. There is a difference.
Safe flying.