mattfish

poison darts are and tree frogs the houseing cost more than the frogs most of the time thats if you do it right youll spend a ton of money just to house them

i would have to agree with Locascio. you have to have precise temps and humidity, not to mention they will not eat and get overly stressed if you dont have them housed right. also i have noticed that the smaller the frog the weaker they tend to be. the bigger they are the more sturdy they will be even if they are babies they tend to be the most successful. but the smaller they are the easier it is to injure them and stress them in handling. temperature is a huge factor as well in fact if it gets just a little colder or warmer then they require could cause serious harm or death.
with my bullfrog i can leave it 2 weeks at a time to go on trips or out on business when i get home he is just fine and happy. i am sure they could withstand much greater neglect so long as they have water. with tree frogs and dart frogs you would not be able to do that. not even just for a few days.
i am not trying to talk you out of getting them. they make excellent pets. but they require much more care then most other species.

I think the dart frog

it kind of depends where you live because some places are too hot and some places are too cold. so depending on where you live i guess that's really how you should evaluate how hard it is to keep certain species.

dart frogs sound tricky and seem to require lots of maintenance. they are really cool though. you can keep alot of different colored ones together. plus they like to move around during the day unlike my pixie. i always thought dart frogs would be tricky but goliath frogs, if legal, would be expensive also just because of the size enclosure they would need.
i was going to trade one of my leopard sharks for a pair of blue dart frogs a while back but the guy never called me back. maybe because he didnt have a big enough aquarium for the shark. but i would have done it.