The only piece of his that I know is his “WARSAW CONCERTO”, which my local NPR station (WBUR) seems to play constantly. It is a pretty good piece-it seems to sound a lot like something by Rachmaninoff.
Anyway, is he a highly regarded composer?
Short answer: no.
The Warszaw concerto is a pastiche he wrote for a movie, and indeed has more Rachmaninov than any other feeling.
EDIT:
More info from wikipedia:
The Warsaw Concerto was written for the 1941 film, Dangerous Moonlight, and continues to be a popular piano piece. The film-makers wanted something in the style of Sergei Rachmaninoff, but were unable to persuade Rachmaninoff himself to write a piece. Roy Douglas orchestrated the concerto. It has been recorded over one hundred times and has sold in excess of three million copies.
So he did not even orchestrate this composition.