After about ten years of experimenting with guitar strings, I followed a suggestion posted on an earlier discussion of guitar strings at mudcat and tried Spectrums by Thomastik Infeld, an Austrian maker better known for their violin strings. Put them on my 30-year-old 000-18 Martin and have used nothing else since. Head and shoulders above everything else I tried. I used to find this guitar a great finger picking guitar, but an indifferent strummer. With T-Is, that changed.
I've often wondered if the quality of American made or branded strings have slipped, like every other metal product made (or sold) in the USA. Boat builders I know complain that US made fasteners (bolts and screws and the like) are much poorer in quality than they were ten years ago. Chinese made metal is even worse. Where are the strings sold by Martin, etc. being made these days? Just as with our clothes and shoes, are they all coming from some huge Chinese Guitar String Factory?
John Pearse strings, which I also like, are made by Thomastik Infeld. I use them on my Nik Apollonio Bell 12 string, as the T-Is aren't long enough. But I think John Pearse knew what he was doing when he hooked up with T-I.