I love STP's, but as a beginner to another beginner- I'd personally wait a while longer before getting. They can be awesome snakes and they are gorgeous, but there is still that potential of an attitude problem and that's a big animal to deal with when it's not pleased. I know I want to wait a while longer before I get one. I don't know about Woma's but they are pretty cool snakes. Dumerils are big 'ol chunky things
What the store clerk said about Hoggs is about opposite of what I've heard from them, but different snakes, different experiences etc... personally, if it was me, I'd get a smaller boa like a Hogg or Dumerils or the Woma before an STP. Or if you do get the STP, HANDLE IT. Handle it as much as they'll allow. Also, go with an older animal rather then young- a sweet yearling may not stay sweet. Older snakes are usually pretty set in their temperament.