SF in English has two problems... 1) it's become branded and commercialised e.g. Star Trek pulp novels and 2) it doesn't know enough about SF in other languages. Reading "Roadside Picnic" is a nice antidote to both. SF is meant to be Science and Fiction, not Pulp and Trash.
As a novel it isn't perfect. I reckon it only really gets going about 3/4 of the way through, but having said that, the first 3/4 ARE readable. Like Lem's "Solaris" it tackles questions about ETs that corporate SF doesn't deal with, like "Can we communicate with aliens?" & "Can we even understand them?". The aliens in Roadside Picnic aren't two dimensional Klingons or Vulcans, but genuinely alien.
Some of the dialogue could do with tidying up too (translator's fault?), but unlike the majority of junk that masquerades as classic Science Fiction in English, it stands up as literature and a good novel in its own right. Theodore Sturgeon's excellent foreword points this out better than I can.
One more thing... you might be surprised to find out that Russian characters are actually thin on the ground in this novel. They seem to be in the minority - apart from Kirill. There are no obvious "Soviet vibes" from it either, political or otherwise.