-Stuarts need a follow up, just one Stuart is not effective on its own.
Agree 100%
2 Stuarts can work in combination to take down even medium armor. Use chain stunning and follow up with an engine critical at close range. Panzer IVs can be reliably taken down with a couple of Stuarts. The Panzer might not even get a single shot off if you activate the stuns in succession. Watch out for Pak or Pup support!
This is a very risky play and a single pak backing up that PIV will punish you and make your double Stuart play a horrible mistake.
-The abilities of the Stuart can be even more useful later in the game when you are facing medium or heavy armor and have armor of your own. Punish enemy armor that's out of position or pushing forward with stunning and follow up with your tank destroyer or medium armor.
This is really the best way to employ a Stuart, getting one and following up with a Jackson isn't as bad as you would think, provided you play smart and don't run into a pak wall.
-My last tip has to do with vet. Did you know Stuarts require the same vet as the M8A1 Howitzer Motor Carriage (which is just a Stuart with a different gun, after all)? That vet 2 Stuart crew can become a vet 2 motor carriage. The reason this is important is for the ability to pop smoke at vet 1. In addition, you don't lose the abilities of the Stuart by rotating out the crew because they are inherent.
While this is correct a high vet Stuart at late game can give you very good sight range allowing you superior field awareness, late game this can be important as spotting the difference between a push and harassment is vital and mistakes here can cost games.