You'll get a lot of different suggestions here. I've used adjustable and moved on - my Gillette Slim and Merkur Progress are on the BST. Nothing wrong with adjustable as such, but I like to choose my handles. They're an important part of the razor for me, so I stay with 3-piece razors. The DE89 has the 2 stud fitting used by a large number of razors and if you stay with this fitting you can swap handles, top caps and base plates. I moved from safety bar razors to open comb razors, which I prefer the feel and design of. So for "more efficient" you have a Gillette Old Type and its clones and the Fatip open combs like the Grande, Retro and Piccolo. All very nice indeed for around £20 and made of solid brass as well.