There is no difference in taste or nutrition between the two. I eat fertile eggs all the time; I just make sure I gather eggs no less often than every three days. (I have a health condition which saps my energy and it's all I can do to make sure their feeders and waterers are kept full, some days. Sometimes I have no problem and will gather eggs several times a day - that's usually on the weekends. It's during the week when I work that I don't always gather eggs daily.)
Embryos do not begin to form until eggs are incubated, either by a hen or in an incubator. Most hens do not go broody to incubate their eggs, so any left in the nests on cool days are perfectly fine for 2 to 3 days. Hot summer days just might start incubation, if it's at least 99 degrees several days in a row.
Obviously, if a hen is brooding on a clutch for any length of time, I wouldn't want to eat those eggs if she's sat on them 24/7 for a few days already! But I will break THOSE eggs into a separate bowl, first, to make sure I haven't picked up a developing egg.