Cider is traditionally made from apples or pear and varies in styles from sickly sweet to bone dry. Cider can basically be separated into 2 categories: craft and mainstream. Mainstream cider was traditionally a sweet, dry or draught from suppliers such as Mercury or Strongbow, but as the popularity of cider has grown many new entrants and flavours have emerged. Brands such as Rekorderlig and Somersby now dominate the market with sweeter, flavoured cider popular with many (especially younger) drinkers.
More recently their has been an emergence of craft cider, which is made by producers who actually crush their own fruit (as opposed to adding sugar to a fruit concentrate) to produce more complex and often dry versions of cider. There are some great Tassie brands doing some really exciting things with cider, give them a crack.