Advantages - two piece / three piece

I have an Vintage Superspeed (One piece, twist to open), an Merkur HD (two piece) and a Muele R89 (three piece). The one piece has some marginal ease of use over the three piece; but I cannot see the advantages of the two piece - I find it more of a fiddle to replace the blade in the two piece over against the three piece. I have to guide the blade over the longer threaded shaft - it never falls into place as it does over the shorter shaft of the three piece. Am I alone? Am I missing something?

An advantage of two piece razor:
- to open 3-piece razor you have to hold tight two pieces with blade inside and turn off the handle - could be painful as you have dull edges of the blade exposed to your fingers assuming the all 3 parts of the razor were mounted really well
- to open 2 piece you have to hold tignt knurled upper part of the handle and turn off the bottom of the handle - it's much safer to the fingers and ;-)