In my search for a new critter, I read up a lot on Sugar Gliders. I'm not an expert by any means, but from what I've read, Suger Gliders are very needy. They need at least three hours of out of cage time (and as they are nocturnal, generally in the evening), but if you have time during the day they would love to ride around in a bonding pouch.
They also do better in pairs as they are social animals (like rats or ferrets ).

They are an "exotic" animal, so they do require a special diet. They need a medium to large cage to have room to run around in. I would imagine they would be on the more expensive side of a smaller animal just because of their diet, cage, toys, etc. Not to mention the price for just the SG.

Here are some links:
General Info
General Info 2
Is the Sugar Glider for me? - VERY good link and is what made me decide AGAINST getting a Sugar Glider.