It has been a while since I formally studied Spinoza's commentators. From the research I did years ago I found Hampshire's work on the philosopher to be a clear exposition of what seems to be a safe, good-working interpretation for an undergraduate wanting to supplement the primary source. Of course there are numerous points of reading Spinoza that are debatable (such as how exactly existence after death supposed to be understood when comparing the first books of the Ethics with the last). For these issues classic collections like the one edited by Green and another edited by Mandalbaum and Freeman are a better place to see where scholars disagree. But this is a great place to get a good plausible overview of what Spinozism does or would look like.