l was told about MBT's a few years ago by the orthotics specialist at our local hospital. His wife is a physio and on her feet all day. She and her colleagues all wore them. l did get some off ebay - half the price of the ones in John Lewis.
You can also get on amazon - trainers that are a copy of MBT's. They certainly help with foot-drop. Recently, someone on this forum mentioned that Clarks had bought out a range of similar shoes/trainers called Clarks Wave. l googled the Clarks Wave site - and have since bought two pairs - one a bright pink nubuck trainer type - and the other a denim blue leather shoe with two velcro straps across. They were both half price. And Clarks do free p&p and also free returns. Very good custom service. Now my OH has bought a pair - and l must say he walks much better in them.
For severe foot-drop - l can whole-heartedly recommend the SAFO-lts a silicone ankle foot orthotic. l have had mine for 6yrs now - very hard wearing/comfortable/ can be worn in any shoe/ and worn without shoes.
lf you look on the Clarks Wave site - you can read reviews on all the shoes.
Hope this has helped.