I am not sure what the more expensive regulator model is (aside from the fact that it is a Smith).
The single stage Cornelius regulator is fine. You may experience EOTD, but just make sure you swap out your cylinder when the pressure begins to drop and you should be fine.
The more expensive needle valve appears to be the Ideal metering valve. It will allow for finer control of your bubble rate.
Also, there are cheaper options out there
Don't forget that if you are ordering from the US, there will be customs as well.