UVLO voltage for LTC2943?

What you see in the datasheet is right. UVLO in datasheet applies over full operating range of LTC2943.

So are you saying that I should follow the number in the table (3.0, 3.3, 3.6V), not the 3.5V in the text?

The text explains the case where "SENSE+ pin drops below 3.5V without reaching the POR level"

Now I am even more confused.  Other than value how does that differ from what is stated in the fifth row of the Electrical Characteristics table?

The Electrical Characteristics table V_UVLO(in table) and UVLO(in text) bit are two different things. When you are in the V_UVLO range you risk the part being turned off. UVLO bit is set when you are below the operating range but still will be able to communicate with the part but will be reading wrong readings, this way the users will get to know they are getting wrong readings.

The Electrical Characteristics table V_UVLO(in table) and UVLO(in text) bit are two different things. When you are in the V_UVLO range you risk the part being turned off. UVLO bit is set when you are below the operating range but still will be able to communicate with the part but will be reading wrong readings, this way the users will get to know they are getting wrong readings.