So I found this information to be interesting and maybe/hopefully useful (please correct the numbers if you find them to be wrong, but this is what I found)
Since 2003, lines -2, -2.5, -3 have overall been losers in the long run:
line...........................Favorite team wins........................................ ..Favorite line wins
-3...... 555 300-255-0... 54.1%....................... 1.87 228-283-44............. 44.6%
-2.5.... 150 79-71-0...... 52.7%....................... 1.79 69-81-0................. 46.0%
-2...... 42 22-20-0........ 52.4%........................ 1.33 19-20-3................. 48.7%
Since 2003, lines -2, -2.5, -3 have overall been losers in the long run:
line...........................Favorite team wins........................................ ..Favorite line wins
-3...... 555 300-255-0... 54.1%....................... 1.87 228-283-44............. 44.6%
-2.5.... 150 79-71-0...... 52.7%....................... 1.79 69-81-0................. 46.0%
-2...... 42 22-20-0........ 52.4%........................ 1.33 19-20-3................. 48.7%