Hit Monitor searches for all of the requesters that you prefer (you have to manually input the one's you want it to search for). It mainly searches for requesters and not specific hits. It will alert you when those specific requesters post. This way you wont miss when your favorite people post... and it's also nice to just leave it running while you do other things around the house that way you'll know to check your computer when it alerts you and you wont miss your favorite requesters.
HitScraper is a TOTAL GAME CHANGER! This is a MUST LEARN if you want to make any real money on Mturk in my opinion. Long story short, you input what types of hits you want it to show you and then let it run. It will let you know when new hits post with the specifications you set. I always have this running when I'm working... and typically I have two running. One for batches and one for surveys (because it requires different settings).
Another tip I want to throw in for all you noobs... Get a second monitor if you can and learn how to use it. It greatly helps with all the different tools you need to turk. I like to keep both of my scrapers and PandaCrazy on one monitor, turk from my other... and sometimes I use my laptop to watch movies while I'm working
There are pages somewhere in the forum that go into more detail on HitScraper and HitFinder. I think I also saw someone post a helpful YouTube video (another great resource for learning to turk). Since it's so slow today, I would spent time learning these tools. It's well worth the time investment as it will definitely increase your income once you learn to properly learn to use the tools. Hope this helps