I tried the Souber and found it absolutely rubbish for the way I do lock mortices in doors which is the door laid horizontally in a pair of choks, it probably works well for doors that are already in place and hanging vertically. It also didn’t really perform all that well on solid hardwood doors, I think it’s best suited for hollow core internal doors more than anything.
Best piece of kit for the job is a portable Ryobi DM-20 hollow chisel morticer but they’re like gold dust and very highly priced second-hand. I don’t know why they stopped making them as they were absolutely perfect for the job.
Bosch make a good corded drill, but I can’t remember the model of the top of my head.
Personal preferences here. Look at Metabo and Fein first. then Bosch.
3 year warranties appear to be standard these days for the better kit but don't forget to register immediately to get that. Put it off for a day and you risk forgetting and losing the extended warranty.
Be a little wary. I used to consider these brands as lietime buy tools and I have Bosch and Metabo that are 20+ years old, but I was very disappointed in a newer Bosch sander that was simply impossible to strip down to replace a failed bearing.
I use a cheapo silverline drill on mine, cost about 15 quid, over the past 6 year I must have used it on about 200 doors. The morticers work a lot better if you give the bits a sharpen every now and then with a diamond stone.
to work with the souber the drill has to spin real fast. it needs to have good bearings and be lightweight as poss.
then it works as intended. never try and use a cordless. unless your drilling for latches. mortice locks are frightening!