Completed in 2001, Sultan Qaboos Grand Mosque is definitely one of the premier Mosques in the World. (It is true, IMHO, that Sheikh Zayed Mosque in Abu Dhabi is even more grand). When I went to the Grand Mosque, tourists were relatively less as it was earlier in the day. The premises are kept very clean and there is staff around in case you have any questions.
The Mosque is around 13Km from the Airport and I had taken a taxi to get there. To take a break in between, I spent some time reading a book I had brought with me, in one of the quiet corners within the sprawling complex.
Oman, overall, is less modern than other Gulf Countries like UAE (for E.g.), but makes up for it with very interesting desert landscapes. Sometime in the near future, I would love to do a road-trip from Muscat to Salalah. I just love driving through deserts …