I would say there is plenty to see around the MCT area to fill 4 days, although the pace of life is pretty relaxed. I would echo mecabq's and IAN-UK's posts which sum it up pretty well.

I'd add scuba diving and dolphin watching as possible activities.

If you don't like Vegas then you may not love Dubai, but the combination of DXB and MCT would make an interesting contrast. I like them both equally, but for different reasons.

Feb is a great time to visit the Gulf as the weather will be very pleasant. And Oman is by no means 'dry'

Thinking of other QR destinations, I'd put AUH and DOH much further down the list. How about BEY ?

hth