I own both a British SLE by a fairly little known maker, S.A. Leonard, and an Arrieta 578, both purchased used. The Leonard is a far superior gun, although it cost me only a few hundred dollars more than the Arrieta. I also have owned a couple of British BLEs, one by Thomas Turner and the other by Westley Richards, and currently own an AyA 4/53. Again, I think the British guns better made and finished than their Spanish counterparts, although the Turner was less expensive than the AyA. Were I in the market today for a sxs I'd go used British before I bought new Spanish.
I've also looked extensively at the modern Italian sxs and find the ones in comparable price range to that of the Spanish sxs to be better engraved but not as lively or as svelte. They seem, at least to me, to be just a bit clunky. On the other hand, the highest grade ones are works of art, but the prices are a good deal higher than the comparable Spanish guns. The Turks are on their way, but probably won't reach the level of the best Spanish makers in my remaining couple of decades.
