I have used ECC+ with normal Joomla registration for a long time now and it has worked flawlessly. I've had 0 spam on my forums. Now I have switched to community builder and spam bots are getting through the registration. Before, I have always relied on botscout for protection which was included in ECC+.
Now, I don't know if ECC+ is using botscout verfication in the community builder registration process.