Easy man for some to hate, easy man for some to love/admire. He was wholly anti-American and anti-imperialist, so it's easy to see where those lines generally fall. Definitely killed a lot of people, and not very human rights friendly at all. But it's hard not to see why those who see America as not so great, as a great person, it takes massive balls to take over an island 90 miles from the US and keep it out of the US orbit for the better part of 60 years and be a constant thorn in the US side.
Personally I don't like him because of the angst he caused the US (all the fleeing Cubans, general death an destruction, inviting the USSR on to our doorstep, helping to make high fructose corn syrup be cheaper than goddamn sugar, taking away one of the party places for the US) but knowing the reasons for his rise, and why he's so popular in Latin America and other countries fighting against the encroachment of big bad America, is quintessential to understanding how we as America can try to salvage our reputation abroad.