The Jagans legacy in Guyana is easy to summarize. Janet Jagan was pushing Cheddi's buttons with a Trotskyist hard line communism at a time when the US was waving the Monroe doctrine in an escalating Cold War. The rest of the Caribbean did move from a colonial society to one of self governance and ultimately Independence without being caught up in the Cold Ward shenanigans. The Jamaica experience does not come close.
While Jagan was orthodox Warsaw Pact, Burnham was almost Maoist (like the cultist No. Koreans) and even had his spat with Dr. Clive Thomas and Dr. Walter Rodney - two South-South Third-worldist Socialist.
Guyanese free-market life was snubbed out with D'Aiguar and Balram Singh Rai - the latter a very conservative Indo-nationalist.
The post-1992 period of Cheddi's PPP went the route that Jamaica's Manley went. But that period was short-lived and Jagan's legacy of a Politburo-style PPP was exploited by Jagdeo in a growing narco-economy that started when illicit routes to Venezuela was opened up in the Burnham years of economic shortages and the US DEA actions in Colombia. Guyanese lost their innocence in that era. Lots of Indos made money and the poor Blacks had no champion. Burnham screwed them royally and Jagan was an able ally - all in the name of socialism in a post-sixties world of global economic turbulence following the OPEC and the escalation of Mid-East terrorism.
In summary: Jagan was an abject failure and disaster to Indos and Guyana.