the salesman was incorrect. a 57/58 is a very good mic to have for many situations, live or in the studio/home

the 57/58 are for the most part the same mic. the 58 just has a round screen with an integral foam pop filter/windscreen. the 57 has a screen more suitable for micing instruments, but can do vocals just fine with an external pop filter (pantyhose on a coat hanger always works)

as for the midi thing, just get a bluetooth mouse if your laptop supports it.

IGNORE THAT SALESMAN.
Holy shit, that is the WORST ADVICE EVER.

It goes against 99% of what's been said on RO about SM58s and in fact on the whole internet.

What you are comparing here are cheap condenser mics with time tested (and yes, inexpensive) dynamic mics. Condenser mics are worse for live sound (they are more fragile and are worse at rejecting feedback), but that doesn't necessarily make them better for recording. Condensers will usually pick up softer sounds and pick up more high frequencies. That is usually good in recording situations. But the ability to pick up soft sounds isn't usually that big a deal for a guitar or voice a few inches away from the mic. Now the extra high end may be something that you really like, even though cheap condensers often pick them up in a somewhat harsh way. If so, you may like the AT mics better than an SM57/58. However, go look at the web sites of some major recording studios. See how many of them have a AT2020 or AT2021 in their mic locker. See how many of them have an SM57 or SM58. It's really no contest. Even if people initially like, say, the AT2020 better for vocals better than an SM58, they often tire of the harsh high end and either go searching for a better condenser or go back to a 58. If you start with a 58 or 57, you may end up going for a good condenser once you can afford it, but the 58 will remain useful. You won't sell it. (Or if you do, you'll regret it and end up buying another.)

On the specific purchase, if you are going to get one mic, I'd get the 57 and one of those foam wind screens. Put the windscreen on and you have a 58.

Like you're hearing - dynamics and condensers are comparing apples and oranges - not much to add to that topic.

But, let me demystify the "why"...

They make a lot more money selling you a AT2021.

Thanks for the clarification guys, I'm glad to hear to it.

With regards to the 57, would this pop filter here:
http://www.axemusic.com/product.asp?numRecordPosition=3&P_ID=2086&PT_ID=164

work better than say:
http://www.sweetwater.com/store/detail/A57AWS/

or would it matter much?

Thanks again guys!

Maybe split the difference - and go with something designed like the more expensive one. The advantage is that you can use it on any other mics you might eventually add to your collection. But here are several to choose from with the same design at significantly lower prices.

link removed

Thanks for the site! I should have pointed out earlier than I'm north of your border. Our dollar sucks and so does customs! I will find something local with the design you've provided though, seems the most universal which is definitely what I need right now.

Thanks agian :D