Reverse Band DL's are the best exercise for improving your deadlift if your lockout sucks. The intial deload of the bands also helps explosiveness off the floor. Use Average Bands. The contrast from bottom to top isnt too ridiculous but you can still overload the shit out of yourself if you pull fast enough.
I dont know where this easy on the joints shit came from though. If you are working hard enough, any deadlift variation is going to feel terrible. Benefits of reverse bands that I have noticed:
Works the hell out of your grip
Teaches you to keep your back rigid through the whole pull
Teaches optimal hip placement
Makes your balls gigantic
As far as carryover, when I got a 900lb reverseband pull in a 7 foot rack in training, I pulled a fairly easy 804 and just barely missed 827. So youre most likely going to be 70 to 80lbs higher than our true competition max. This has been true for some of the other guys I lift with as well.