Both are fully automated. Better to use semi or manual things. if you cross 200+ marks a day twitter might ban you.
i tried tweet attacks for a bit but all the twitter accounts got banned within a day which annoyed me. They say buy all these proxys which are a complete rip off like 1USD per proxy per month so if you want to follow on a big scale it becomes incredibly expensive. There refund policy is fine if you don't buy it through an affiliate.
I've tested some account both tweetattacks and tweetadder use tweetadder if you want account live longer use tweetattacks if you need fast tools with many function like retweet attacks and wait&reply module that tweetadder can't do
Tweetadder is probably the way forward for me, however, when you are just starting out you may want to consider the vast and many FREE alternatives to getting free twitter followers. There are tons of ways to do this, as well as Youtube and Facebook likes. People are simply too lazy to take the time to find this out. I've been working on this very subject for some time.