This character wrote four symphonies apparently and I've been listening avidly to the first two- No.1 has obvious overtones of The Poem of Ecstasy, and No.2 similar near-quotes from Pictures and Petrushka: it's basically early Shostakovichian brazen eclecticism and arrogant dispatch, but I think without further promise and a bit wayward.
Six symphonies and a chamber symphony, actually. ;)
I think the first symphony and chamber symphony are the pick of the works I've heard: the music he wrote after Stalin's 1936 crackdown has little of the vitality of the earlier work (apparently the composer retreated into alcoholism and solitude after 1936, and his music certainly retreated into "acceptable" Russianisms).
I still think the first symphony is a major work, and it's a clear influence on Shostakovich's slightly later fourth symphony.
I think that he is a very fine composer. Symphony 1 is the only symphony I know which compares with Shostakovich No 4. I have two CD versions. My other favourites are the more traditional but moving Symphony 2 and the last one; No 6, with its echoes of Boris Gudonov. Like Mussorgsky, Popov sadly drank himself to death after being subjected to the critical disapproval of the regime in 1948. The collapse of Olympia means that his music is likely to become even less well known unless an enterprising company takes it up. Maybe Regis or Alto will reissue the Olympias one day.
I find Popov of only passing interest and can hardly agree about a comparison with Shostakovich Fourth- there's certainly the similar idiom but Popov lacks the same insight into the flow of ideas that makes the Shostakovich so compelling, and I'm not sure its brazen eclecticism rises much above the youthful and wilful; the parallels with the end of the Poem of Ecstasy at the end are also just too obvious...