Personally, I prefer spreadsheets for timelines because I can use the columns to line up my characters side by side and compare what they're doing simultaneously. Also, I can add columns for miscellaneous relevant information (for example, in my books, I need to know when the full moons are.)

So, I might have a column with the date or time; a column to mark if it's a full moon; a column to list what Mildred is doing; a column to list what Bobby is doing; etc.

It's much easier to manipulate timelines involving multiple characters in a spreadsheet, in my opinion.

Cheers,
Michelle