Oman Air’s Business Class Product is a fully flat bed and only 4 abreast. Their First Class offers even more (though apart from exclusivity, I cannot imagine much more being offered in terms of comfort). Their Business Class product would rival the First Class product of many other airlines (including Qatar, Emirates and Etihad). Also, I think Oman Air offer a complimentary chauffer drive service at both ends. Connecting flights from Qatar not very frequent and Abu Dhabi I would assume the same. More frequent connections from Dubai but many are actually operated by Oman Air (codeshare with Emirates). BA also fly to Muscat (thought not non stop as far as I am aware).
On hotels, I have stayed at the Shangri-La twice. Wonderful resort and great facilities. I have never stayed at the Al Bustan (which I think has been recently renovated and is operated by Intercontinental).
Enjoy your trip…