Maui has great surf spots for all levels of surfers from beginner to expert (during the right conditions). South and west shore waves will be longer and more gentle in the summer months, great breaks to learn to surf or to longboard. On the north shore, in the winter, waves will be high octane and powerful. Spots like Peahi, aka Jaws can produce 40-70 ft monsters. Maui definitely gets a lot of swell, but the surf is seasonally fickle and a lot of swell is blocked from the Big Island, Molokai, and Lanai.
The best breaks on the island are reef breaks. The reefs help form perfect, clean waves but are also a hazard for surfers. Cuts and scrapes are the primary issue, but surfers can get stuck underneath in the rocks and caves. The reefs are also home to an abundance of sea life like urchins, jellyfish, and sharks. Maui is a really windy island, that means some spots close out early in the day and there are a lot of side shore winds. Great for windsurfers and kite boarders. Not so great for surfers.