-Collins wins. (your neck of the woods so you might beg to differ as you have unique insider yankee insights i guess)
As I said a while back, Collins was somewhat on a track to lose but then Trump came out and said that she was a loser and would not campaign for her "because she was not worth the time." As to be expected, that has helped her considerably and brought things back to a 50/50 scenario.
Also, as I said, this is Maine's (or any state's) first election using a "ranked ballot" system whereby the calculation goes to voters second choices if their first choice choice falls below a certain threshold (ie. the votes for third parties get re-assigned.) No one knows how that will go. I heard that it would work against Collins, now today I am hearing that ranked choice might help her. I don't know. I am out on the west coast and know susan very well but not her opponent nor the third parties on the ballot.
In general, I think she has moved up a point since Trump disassociated himself with her, and 1 point is worth its weight in gold in that race. But it still would require the voter to vote a split ticket because Biden is going to take the state. Mainers are fiercely independent and have a long history of voting split tickets but you know- it's like Austin Texas now. It is hard to calibrate the New York and Californian impact. She will definitely win the northern two thirds of the state but the Portland area is sort of an extension of east coast seabord.
As I have said before, Susan Collins is the last republican in either Congress or the Senate from New England. So the atmospherics are against her.
If you put a gun to my head, I would say that she will win by half a point. Mostly because her hometown region in northern maine is going to vote for Trump and give him that one electoral vote so they will check off Susan Collins while they are voting too.