Pro:
-$5 trade (all below is from their site)
$5.00 for market orders placed over the Internet.
$5.00 for limit orders placed over the Internet.
$5.00 for short sells placed over the Internet.
$5.00 for stop orders placed over the Internet.
$25.00 for broker-assisted equity transactions.
-can put a limit sell right when you buy (I heard that Ameritrade will not let you do this - but I don't know, this is the only one I know of)
-Real Time Streaming Quotes for No Charge.
-Stock Ticker for No Charge.

Con:
-not the fastest traders in the game. Sometimes they are slow and you may miss the target that you want. But if you are new to the game this may not be the major factor (I guess you get what you pay for - it IS only $5)
-Block Trading Fees applies to all orders for OTC-BB and Pink Sheet stocks of 100,000 shares or more. This fee is $.0005 per share or 1% of the principal, whichever is lower. (from their site)

They do have Level II
Level II Quotes
$20.00 first month.
$40.00 a month each month after.
No set-up fee.

Good luck to you