Coimbatore has many star hotels like le meridian, Radisson blu etc.
You can surf on oyo's too they have wide range cheap and classy hotels at both Ooty and Coimbatore.
Ooty and Coonoor has good homestays , Chec out I India in ooty , it was a british mansion , stay was amazing :) Coimbatore is more of City types , You can also stay in Isha foundation as well
Coimbatore:
Radisson Blu : It's near to Coimbatore Airport. INR 5,500 per night onwards
Vivanta by Taj – Surya: It's near to Coimbatore Railway Station. INR 6,500 per night onwards Ooty:
Zest Danish Villa : It's club Mahindra property. INR 5,500 per night onwards
Accord Highland : Best for couples. INR 5,500 per night onwards
United 21 – Paradise : For best scenic view. INR 4,000 per night onwards Hope it helps. Thanks.