One of those never ending games...
Apart from the lengthof the game (which for me is too much) Summoner has some cool features. Its spell casting and Fighting mechanism are quite unique and more enjoyable than in other games. Graphics are also not bad for a game that was released in 2001. And although there are sub quests in the game they wont effect the final outcome hence just be there to increase your experience and help your character level up faster.
Overall although you might get tired of playing this game (especially at the end). Its likely that you will enjoy it enough to keep playing it till the end.