I'd say trial it for a few months and see how you go. Our two boys 4 and 2.5 share a room and initially the oldest wasn't too keen on sharing 'his room'. However, after a sleepover at g'ma & g'pa's where they shared a room, he was all keen for his younger brother to 'sleep over' in his room. He did ask after a few days when his brother would be returning to his own room. It went well for the first month or so and then they started playing up, taking, jumping out of bed, etc. We knew that the novelty would wear off, which it has and the eldest falls asleep really quickly. The only downside is that they both wake up really early - one will always wake the other one up.
It does make bedtime stories quicker too, as one sits on the lap and the other sits on a bed and we read the same stories to both of them.