You'll find a full range of options, from small budget hotels to Agadir's five-star behemoths. In Essaouira, many old traditional family homes, or riads, have been restored and converted to beautiful guesthouses. In summer it's best to reserve rooms in advance, and for the more upscale boutiques, you may have to book several months in advance whatever the time of year. There's also an increasing number of rental apartments in Essaouira and "apartment hotels" in Agadir; both offer self-catering options.
The Souss has some choice small hotels ranging from simple auberges (inns) and restored riads to former palaces and one luxury hotel that's among the best in Morocco.