I think I'm with Bobbsy, mostly. My spin on it is this- First, there are better entry level condensers than the 990, especially for vocals. I like this:
Marshall Electronics MXL V67G | 8thstreet.com | Call 1-800-878-8882 | Most Orders Ship Free!
Regarding dynamic mics, condensers and dynamics are like the yin and yang of microphones. They are different tools, like hacksaws and screwdrivers, and learning to use them both is the beginning of being a tracking engineer. Unlike many people, I am not particularly impressed by Shure SM57, even at its price point. It's a perfectly good stage mic, amp and snare mic, but there are lots of others. Where lots of people use a 57, I'm more likely to use the discontinued AKG D770, or Sennheiser e835. If you do buy a condenser, what the hell? Spend an extra $25 and get one of these:
Behringer XM8500A | 8thstreet.com | Call 1-800-878-8882 | Most Orders Ship Free!
You'll be shocked at how much it does *not* suck, and will give you the opportunity to learn to use dynamics without spending a lot of money. In my opinion, the 57 is overrated. It became a standard in the 60's in the U.S., while Europeans were using Austrian and German made mics because they were cheaper in Europe. Many great European dynamics were simply overlooked here. Get on ebay and find a D770. It will not disappoint.
You are right about one thing. That deal for the 2 MXL mics for cheap has been out there for *years* now, which tells you 2 things. One- they made too many of them, and Two- nobody is very impressed, and they can't even give them away. Good luck.