I use these as well as the SM-58, Beta 57A, and Sennheiser E835 for vocals. The Beta 58A has a tighter pickup, has a hotter output, and is a little brighter than the normal 58. I certainly grab a Beta 58A when I'm expecting a muddy and noisy sounding stage (loud guitar amps, background noise). Esepecially if I'm underpowered and lacking in the processing department. It's sound is a little brighter and it can be a bit much on some female voices, so I'll often switch over the the 58. The downside of the Beta 58A it doesn't sound as warm as the 58, in some instances it can be a bit too sterile in my opinion. But other times it'll clean things up for you. Overall, the Beta 58A is worth it if you're budget supports. Otherwise the SM-58 does the job just fine. The SM-58's high production/sales and lower price make it more affordable, which is nice if you need multiple mics that are GOOD and will last. The main difference between the two is marketing IMO, so don't buy into it unless you want a different, but similar mic. I personally like having the option of choosing between the two, it's nice having the beta for when you need just that little extra of everything (pickup, output, brightness). But sometimes, less is more. It's not hard to over do things, and it can sound sterile, that's where the 58 comes in.
The E835 is great contrast to the 58. It has a great anti-shure (not that shure is bad, but instances some mics will sound better than others) vocal mic. It's much cleaner and smoother sounding then the 58. But it's no where as strong and widely accepted as the 58. And it sure (no pun intended) isn't as warm or natural sounding as the 58. But it's definitely a mic to have around when you need something to contrast the zillion 58s you already own.
The Beta 57A is such a versitile mic, more than the SM-57 IMO. The regular 57 is useless as a live vocal microphone, but it works well for speech (w/a little distance and sometimes a screen if needed) and recording vocals. A popscreen is often distracting, and many refuse to use them because they aren't comfortable with it's feel. I'd rather kiss a solid material rather than felt which soaks up moisture (icky). I know you can change the screens but you'd be suprise how quickly the screens soak up. Sometimes it only takes a song to turn it into a sponge. The Beta 57 is however useful in so many ways. I have a friend who actually uses them as overheads, they have a real nice and clear bright sound. Anyways, back on topic, the 57A is the mic I grab when conventional vocal mics sound to dark and muffled. It's bright sound often makes a brillant night and day difference for vocals that "just don't sound right" and/or that don't cut thru. It sounds like a bright E835 style mic but with the shure warm and natural sound.
If I had to pick on of the four it would be the 58, because the only reason I keep around the other mics is when the 58 isn't doing it's job.
I use four Beta 58s along with two SM58s. The Beta's definatly have have a nice pickup and a good sound to them. There was one choral concert I was working and I didn't have enough time to bring out the SM81s, so I just used the two Beta's and they filled in well. They have a nice gain before feedback. Overall, a nice mic to have around.
Has anyone worked with vocal mics from manufacturers other than Sennheiser and Shure? I'd be interested to know what models from manufacturers such as AKG, A-T, Neumann, and others are good for live vocals, and how they compare to one another as well as the SM58, Beta87, e800 series, etc.
Take a look at the Audio-Technica AE4100 for vocals. They are outstanding. I had a lead singer bring his own to a show that I was FOH for (I usually use 58's and beta58's) and I was impressed. It is built tough and takes plenty of abuse....and still gives a great "in your face" signal that is difficult to keep from overwhelming the rest of the other mic's on stage.
I still stick with the 58's, though. They are the standard and vocalists know how to handle them. The 58's are also about half the price...always a plus.