I don't use anything either. When I get a notification that I have a new follower, I follow back manually. Because truthfully, I don't want to follow everyone who follows me. The vast majority I do, but there have been a couple of instances when I chose not to.
I don't use anything either and like Lori I follow back manually when I get notified. You don't always want to follow everyone especially if they are spam accounts. It would be interesting to see what tools are available though
I had one creepy guy try to follow me but after I checked him out, I blocked him! I was able to see where he kept tweeting some woman asking how to access her "adult" site. At some point she apparently blocked him because then he was begging for her to unblock him. Seriously??
I use tweetdeck (free) but I now check out who I follow back. It's not just creepy peeps I won't follow but there are some others that I just have no interest in and don't want to see their tweets. I try and make mine meaningful!
I generally only follow people who I've checked out myself. That's both on my personal and business accounts. So I don't use an auto tool. I think with so many things able to be automated and on auto pilot that I just like having that manual control over some things. Esp. who i follow associate with on social networks. just my $0.02. hope it helped in some way