We've sailed with Virgin 4 times in the past year, and have 3 more booked. Princess has offered us deals as low as $50 per cabin for 14 day sailings, and we didn't consider them for a second.
Besides no real dress codes, there's also no announcements, no art auctions, no photographers, no added gratuities on drinks, etc......the vibe on board is of acceptance, not exclusivity, (except for Richard's Roof Top which is for suites only)