Paul, AKA "Cellman", at EM3EV.COM sells the same kit, with better quality batteries, (more on that later), at competitive pricing. He has been in business a lot longer, and has much better customer service. You have not heard his name as much as he does not employ paid shills to pimp his products all over the internet. This is a well-known tactic of Luna.
You will need to charge at work in order to avoid draining your battery dangerously low, that is where a well-made, high-quality battery becomes important. Comparative teardowns show conclusively that Paul's batteries are indeed of better quality than most others, specifically Luna's.
If you have a problem, Paul will bend over backwards to get it resolved, and there are several documented instances of this. Eric Hicks of Luna will call you a liar and insist that you never purchased anything from him, then demand you delete all public mention of the problem before providing warranty support. There are many documented instances of this.
He has also been involved in knowingly selling defective products, and has twice placed a large cash bounty on personally identifying information for those posting the truth about his operations, a criminal act in the US. I am one of those persons.
You should also be aware that the use of a mid-drive poses a strain on drivetrain components far beyond what they were designed for. Chains and gearsets will require much more frequent replacement. May be the best choice for your needs, but a possible alternative, such as a hub motor, should be investigated.
You should be aware that every single new user gets the exact same recommendation that you did, a Luna mid-drive. Not one single time have any of the Luna folks recommended the Xiongda 2-speed. Would you like to know why, as, by specification, this kit would, theoretically, come close to matching your needs? They won't tell you, but I will.