Sweet and a little sour.
Sweet beet pickles are often flavoured with cinnamon and clove and allspice as well as sugar and vinegar (either white or cider), some cucumber pickles are flavoured in the same way, although some don't have as many spices. A lot of chutneys have a similar flavor profile.
If you haven't had one before a jar of pickles is pretty inexpensive, just go for it.