Is an object with value typically an object with odds more than 3.5 or so ? No, an object can be a valuebet with odds of just 1.30, or 1.20. It all depends on what you think is the objects chance of winning the game. If you think a team has got 50 % chance of winning the game, odds above 2.0 represents value. If you think the team has only got a 40% chance, it's no longer a valuebet (with odds =2.0).
Objects with good value are objects which will give you a positive payoff over time.
So if Sheff. Wed has got 10.0 for a win at Old Trafford, it is a valuebet if you think Wednesday will win more than 1 out of 10 similar games.
The formula for finding an objects value is:

ODDS * PERCENTAGE
>= 1.0
100

Percentage is your subjective opinion on the object's chance of winning the event. If the result of the above calculation is a number greater than 1.0 the bet is a value bet. If it's below 1.0 it's not a valuebet, but it can ofcourse still be a good bet.