I may be mistaken, but I was under the impression that delivery reports are only viable if you're sending to somebody on the same carrier, and even then you can only request a delivery report, doesn't necessarily mean you will get one in return. And even then it only verifies that it was Delivered, and not necessarily Read.
I have a BB device myself for work, and don't mind the Delivered and Read status as it is essential for inter-corporate purposes (but then too, I limit my BBM messaging to work related discussions only). I can't stand it for personal use though. I'm very good at letting people know that I simply am not accepting calls or messages for whatever reason (be it I'm busy working, eating lunch, at a movie, or simply in no mood to respond). However, no matter how diligent I am in that regard, people still feel like they're entitled to an immediate response simply because they know full well I have my phone with me at all times. Not many people respond well to the "I simply wasn't taking calls/messages" statement. For that reason, I prefer my personal correspondence to not have a Delivered/Read status. Many times I will read a message sent to me, but decide I will respond later when I get around to, or feel like it.