Against decent opponents and 1/2 pot sized bet, I raise it and disguise the draw especially if it is an obvious draw like 2 sequential cards or rags with two low flush cards. You have the bonus of possibly taking the pot there, possibly getting a free river card and building the pot so when you do hit you can get him to commit his stack. If you have both an oesd and a flush draw you better raise that because you are the favorite at the time.

I hardly ever call a draw, if the bet is so weak that the pot odds are way in my advantage to call, I usually raise to try and take the pot.

Edit: yeah that doesn't answer your question but i don't think that the slow v. fast call makes a bit of difference.

- sed