Bettas are a pretty fish. I thought about getting one, but I heard that they tend to be more work than just goldfish. Plus, I would like to have more than just one in a container.
Bettas are easy, but you can't have more than one, and you can't have anything else, except maybe a snail, in the tank with a betta! Our Mr. Lincoln is a betta; he's bright red. He's our 4th one, and we've had him about 9 months.
Our first, Howard, lived almost 5 years. The second, Emeril, lived with us about a year; we gave him away when we moved, and he lived several years after that. The third, Thomas Becket, got the fin rot and died after about 6 months.
I had a Beta in Vegas, and he was a cutie. I had a one-gallon tank for him, but he knew when feeding time was, and he always came to meet me when I had been gone, even if it was just outside to set the hoses.
I named him Alpha; he was blue, and always wanted me to sit close to his tank so we could "talk".
Because of their nature, they should be isolated from other aquarium denizens, and especially other male Beta, as their "street name" is "Siamese Fighting Fish." They are carnivorous and in their natural environment, they are cannibals.
It is good to have a glass wall between them and the other fish in your aquarium. But you can start out with a Beta...they are fun.