I own a DVX100 and it is great. The b they added a smoother zoom and some other features. For event videography and most commercial projects I think the DVX100 is fine. I’ve never used the “b”. I think it depends on your budget and what you are using the camera for. The images are beautiful on all these cameras especially with the 24p setting. I’ve used mine for broadcast television commercials right here at my work. This compares the “b” to the “a”: https://www.dvxuser.com/articles/100b/
Sorry about the delayed response. Heh, they’ve been pouring it on all of a sudden here. But hey, yeah, I was using spacebar and zero RULES!!! I’m sure that is a totally basic thing.