Have used both the Lefeet S1 and the Blacktip.
Preference?...Hands down...Blacktip.
Why...(2) 9 amp hr Waitley batterys... last 3 full dives. Those are at 118', average speed 3, run time of 65-70 mins, and trigger time about 35 minutes per dive. Used to blow bottom... yes, I am a "tooth" diver.
Can excavate 3-16" sand and broken rubble on speed 3-4....in about 15 secs or less.
I dive doubles with deco bottle side slung...
Blacktip is a JOY to backroll with, ( only 25 lbs) and doesn't create a hernia when boarding boat.
Battery charge in a matter of hours. Never had ANY kind of flooding issue. Only thing I've had to do was make sure to blow out the trigger rod, sand or shell bits.
No brainer....Blacktip hands down.
JMO
P.S. That scooter has made me about 20K since last Oct....