Out of those three... The 820. But the RRP for all three are above your budget. Im assuming youre looking at new only? Budget in a single walled double filter basket as well ~$30. I havent used any of these machines, but I did own the Sunbeam EM3600. They look very similar. Except for the better quality group handle - which will help temperature stability. What about the EM4820?
To answer your question, with that budget, and those options. The 800 with some single walled filter baskets.
Does that help at all?