All sites and apps have time wasters and flakes and just odd people. No way around that, it is just like a gay bar. i live in boystown so Grindr occasionally works, I always tell them up front that I"m BB only, although I can't put that in my profile. There's some nut nearby that enjoys flagging profiles that mention BB. Admittedly, a lot of the guys I meet on Grindr are just looking to either suck or get sucked, and depending on my mood, that's ok.
BBRT has been hit or miss every time since I've been on it starting in 2011. Because it isn't as well known, there are fewer guys on there and in a city as big as Chicago, they can be quite far away. I get increasingly annoyed with too many ask me's in the profile. At least I know the sex will be BB and no one there is going to lecture me.
Scruff tends to be the best app as there are very few 25 year olds that are only looking for twinks. It's main annoyance is that you can't go back to read the whole conversation. While I don't usually have long chats on there for a hookup, i'm occassionally on there at work and setting up something for later. If the guy and I end up chatting for a bit, then I can't go back and read the first part where he tells me what hotel he's at