I'm a bit late to this party but I own two Scubajet Pro's (the new version, not the Kickstarter ones) and a Blacktip Tech, I also have the smaller tube for the Scubajet.
Both have their pros and cons.
The Scubajet is well made all metal design and features proper waterjet type design and the pro version has 4 x 100w batteries (the non pro version has two batteries) that you can separate to take on a plane (I recently took mine to Palau), the unit weighs 5kg (11 pounds) with the batteries, however it is also 2kg negative buoyant in the water (this is a bit of a pain but only when stopped and you get used to it and its small size is easy to swim around with and/or clip it to yourself)
The display provides good information on the battery run time, speed and depth; the battery runtime is pretty accurate. You can also configure the way the grips work so you can use it one handed, typically I will use mine on its side and it's quite comfortable but you do need to keep turning it to see the display (they were meant to be releasing a single handed controller, also the handle part is detachable that also allows you to attach the scooter to a SUP or kayak)
I have done a two-hour 4km (2.4 mile) dive in sidemount with the Scubajet and it handled that without a problem.
The Scubajet is rated to 60m however I just recently flooded the hand controller part at 30m, but I have read that someone has taken theirs to 50 meters.
I wouldn't recommend the Scubajet for cave diving as it will certainly stir up the silt as it creates a lot of thrust (enough to press your inflator button on your drysuit!)
The Blacktip is a beast in comparison, it is big and bulky and depending on the batteries it will weigh between 11-15Kg (24-33 pounds) out of the water, but it is buoyant in the water but will be nose up.
With 9Ah (~162watt) batteries I have flattened in an hours usage, but I have done 80+ minute runs with it with life still left. one of the issues the Blacktip has is that you need to disable a soft start feature to stop it from going into an error state when stating and this basically disable the battery meter, so it makes it hard to judge remaining runtime. one of the advantages of the Blacktip is the flexibility in the batteries and it uses common power tool batteries and therefore you have selection of small or larger batteries that can lighten it or extend its run time.
I also find the I end up with really sore wrist after using the Blacktip from turning as you are trying to turn a large, long mass in the water and it puts strain on your wrist and the Blacktip is certainly not as agile as the Scubajet.
On both scooters I have designed camera mounts to fix my large dive camera, housing, and lights to and both scooters handle it well.
From personnel preference I would say the Scubajet is way more convenient than the Blacktip, it fits under the seat on a boat, and I can giant stride in with it, it's agile and it is easy to enter and exit on shore dives. It's also multipurpose for SUPs and Kayaks that help give it a better return on investment.
And the Blacktip has it on duration as you have the flexibility with large battery options (albeit potentially without a battery meter) so it is better for exploration dives.
On a support side, both DiveX and Scubajet are pretty average.
I did look at Lefeet when I was looking at buying my first scooter and I just found their marketing too good to be true, the runtime claims for the battery size just seemed to be BS and it was so over hyped and being a Chinese brand, it just came across as cheap, whereas Scubajet is Austrian made and Blacktip is US made.
Hope this helps even if it was a bit late.