I have a B70, no issues, but I hate it. It makes terrible coffee, even when I use my finest roasts (old timers may remember I am a bit of a coffee snob). A $10 coffee maker makes a better cup.
Pros are that it’s convenient and quick.
Cons are that it’s expensive to buy the K cups, the K cups are pretty bad coffee, and that it’s quick. The brewing process is better if it takes time, not when water is forced through a hole in 30 seconds, so a drip brewer does a better job. Also, the biggest cup you can make is about 8 oz, more than that and it’s too watery.
The My K cup lets you put your own coffee in, so the expense is not a issue. But it is a pain in the neck to clean, and it doesn’t produce a decent brew. Also, you can’t put in more than 1.5 tbsp of coffee at a time or you will get a mess. So 1 small cup (8 oz) at a time, then you have to clean it before you can run it again.