Absolutely! Their first few albums in the early 70s were great. Very sophisticated, beautiful European (i.e. classically influenced) progressive rock.
I actually had the privilege of meeting Thijs van Leer in 2004, when the recently-reconstituted Focus played the ProgDay festival in North Carolina:
ProgDay
Very friendly fellow...who seemed genuinely surprised and delighted by the overwhelmingly positive response from the audience - some of whom were mere toddlers or even not yet born when Focus enjoyed its initial success years ago.
MM