Synthetic corks are attractive to use as one would expect less failures compared with real cork, due to inconstancies in real corks and due to potential TCA issues. As it turns out some of the synthetic corks I have tested give off undesirable odor. I first noticed something off with the aroma of a wine, and noticed that the synthetic cork had the same "aroma". I opened other types of wines with the same synthetic cork product and found the same odor. I can best describe the odor as "burnt rubber". These corks had been in bottle for 1-5 years but all exhibited the same odor issue. I do not want to divulge the wine or the cork, as my point with this post is to point out a real potential issue with synthetic corks.
Another issue that synthetic corks may have, is the higher amount of oxygen ingress, potentially aging the bottle content faster than a real cork.
At this point I recommend that a small bottling trial is used for determining the suitability of a synthetic cork. Other considerations would be around life span of the wine, whether the wine is expected to sell immediately, or to be kept for aging.