Pedantically the first would be correct, but I'd go with the second one because it doesn't jar.

Either ‘Is Marella Cruises Ltd Good for Solo Travellers?’ (which makes it clear that ‘Cruises’ is part of the company name where the use of capitalisation makes this ambiguous) or ‘Are Cruises with Marella Cruises Good for Solo Travellers?’. The goal shouldn’t just be grammatical correctness but also something that is easily read and understood.