Embryo are hit-or-miss, certainly. What I've heard with Mariano has been live concert recordings, which didn't faze me as much as some of the stuff they recorded without him in North Africa, Turkey, and the Near East - ethnic shit with troupes of local musicians. Embryo's Reise, for example. There's also one hell of a 2LP set that comes enclosed in a cardboard box, and was for a time available by mail order through the band. It's phenomenal, but not so easy to get these days... Surfin' is not so great, though.
Some of their work, ironically, reminds me a bit of the Don Cherry ethno-jazz material, which fernando may get a kick out of... Organic Music, Ankara, Blue Lake, even the orchestral shit.
Soft Machine are a good call, but I'd steer more in the direction of Five than Six. Just my personal preference, though - it's more "free fusion" than anything I guess.