I did a BA/BT external and personally I loved it. For most of the time I was studying I was also working pretty much on a fulltiem basis. The pros are that you can studty when you like, you are able to arrange the study the way you want to get the assignments done, the help that is available is absolutely fantastic too (in my experience, actually from what I've heard the help can actually be better than being on campus), and there are discussion boards for topic conversations for all external students.
Im not one of those people who would have lasted at uni, I like to study at my own pace, I prefer not to have the competition in the classroom either. But thats me.

For me there are few cons to it, although finding a library near by that stocks the books you are after can be hard, being responsible for your own work and achievements, you have to be good at time management to get that done. Also it can involve a fair few emails and phone calls when you need to talk to lecturers but these days they are pretty good at getting back to you asap.

Goodluck with what you decide!