I did not time it; but estimate for me to sign up is 5 minutes. Problem is two fold. The password comparator algorithm does not operate in real time and when you have inadvertently typed in non-matching passwords you are forced to go through Captcha another time. I use complex passwords and it took me 3 trips through captcha before winning. Yes, I could have taken more time and written my new password down and typed it in with 1 finger, 1 letter at a time and not made mistakes; but old habits die hard.
Second problem is Captcha photos; some of them are such poor resolution in the distance that you cannot be sure of contents. Also some of them like storefronts have photos that are a matter of guessing if they are store fronts because there are no store names, doors or other solid clues that the photo is actually a store front. I think Captcha needs more quality assurance testing by 3rd party outsiders of their product.
I have used captcha before and as always (on other websites) it is a frustrating experience.
In the interest of appealing to a larger membership and not turn off prospective new members and potential paying subscribers, I suggest you try to make the sign up filter more user friendly by addressing the above difficulties. I have seen very creative, simple effective "Captcha" substitutes on other web sites. I am sure with a little effort your creative people could make a unique to malware; but more foolproof robot detector algorithm in lieu of using Capthca.