I probably shouldn't be telling you what I'm about to tell you, it hurts my chances but here goes.
A friend put me onto this thread and it could be lucky for you that he did.
I'm already booked on a HNL-SYD cruise on Radiance this September, so 50:50 chance you're looking at this cruise.
This will be my 3rd cruise on RCL, of which my other two cruises have both been 2 week cruises (Legend of Seas and Rhapsody of Seas). In both instances I was in an interior cabin.
Interiors have the benefit that they are dark, so if you like a lazy sleepin on your cruise, that's one of the benefits. I tend to spend very little time inside my cabin and more out of it cruising about the ship doing activities, lounging by the pool or in the hot tub, or at night getting out and having a few enjoyable drinks. Most time spent in the cabin is sleeping and other nocturnal activities. Interiors are also better if you get a little sick on ships, the trip from NZ to Sydney can get quite bumpy, I remember eating at the front on top of the boat and almost feeling like the food went back up my oesophagus. The general rule of a boat is, the closer to the centre of the boat and the lower the cabin is, the more stable and less rocking you get. I would get up just in enough time to be at WindJammers a bit before breakfast closes up and lunch starts, mould the two meal times together.
So, Balconies mean that you are on the outside of the ship and you get light into your room, which might be a good thing if you want the light to help wake you up. You will also get a little more room in your cabin as well. Balconies have the same tip rates as Inside and also you get the Same Frequent Cruise Points as Inside. Balconies also result in a room higher up in the ship as well, putting you closer to the top deck and you go down to get to the main dining decks. There isn't room for a lounge on the deck either, it's a chair.
On the cruise mentioned above, I'm actually going in an Oceanview room. The goal is to get an upgrade to a Balcony room from there (hence why I shouldn't be telling you this). Upgrades are given on a Frequent Cruiser basis, and a two week cruise gets 2 points. The other thing is that repositioning cruises (which this leg is) tends to have much less people on it and thus the chance of upgrades is much much higher. This is also the reason I have done other cruises first and left this one until have more points up our sleeve.
The main issue you need to think about is money. If money is no object then go for the Balcony, if it's a bit tighter, then go for Inside. Shore Excursions cost a bit of money and as you know, you don't really want to skimp on things on the boat, maybe some more finer dining, nicer bottles of wine, coughtails by the pool or evening drinks at the club upstairs or a flutter in the Casino. I'd be also unlikely to spend much time on balcony with sunset, more likely to be in a bar for pre dinner trivia or at a show.
Well I hope that confused you some more. Any questions, shoot.