I perfer decimal scoring.
You don't lose points because of milestone levels (if you get 1 point for every 10 yards rushing, decimal scoring is .1 for every yard 79 yards is 7.9 points and 70 yards is 7 points; or if you do whole number scoring 79 yards is 7 points...the same as 70 yards)
You also are less likely to have a regular season tie.
The only reason to use non-decimal scoring is... well actually I can't think of one. Non-decimal scoring was the standard back before live scoring was invented, when you had to bust out your newspaper and manually calculate your own scores on Monday and Tuesday. There is really no reason that non-decimal scoring should be around at this point in time.