I have used my Ryobi 18V lithium battery one. I use high speed till it reaches the ground and then shift it to low. When you go to low and the jack is on the ground and lifting you had better have a good hold of it or it well twist your arm.
I have 2 batteries for it and I can load an unload the camper a number of times before the battery runs out. I use it all the time to lower the rear jacks to stablize the camper as it is much faster than using the electric motor on the jacks. This is on a 10 2 CDSE NL which is not a real heavy camper but not a light weight either.
This is the one that I useI don't know where folks get the idea that an impact doest beat on the nuts. I know both my electric and air inmpacts when trying to undo a tight nut beats the heck out it. That is the purpose of an impact is to try to jar the nut loose by hitting it and then back of a bit and hit it again.
The difference between a hammer drill and an impact is the hammer drill hammers from the get go but an impact well run smoothly till it gets resistance and then the impact starts. Go by a tire shop and listen to the impact wrenches hammer away when they are trying to take off big truck tire.