They are indeed close in head geometry. The Merkur has a heavier handle and deeper knurling which provides a somewhat better grip and also shifts the balance. Frankly I prefer the somewhat head-heavy balance on the Lord and didn't ever have any problems with its grip. Another thing; the Lord centers the blade evenly and perfectly every time while my Merkur doesn't. Not a real problem but strange that an almost 3 times more expensive razor can't be made at least as good in that respect.
FYI I shave most of the times with the Lord and use the Merkur as a travel razor. Except when I take the Lord on holiday too....Both are rather mild but capable of giving good 2-pass shaves nonetheless.
I must to the barber's, monsieur, for methinks I am marvellous hairy about the face