#125 TECHNIQUES - SNOT piece comparison
When put side by side, these two pieces may look very similar. Yes they both have 2 studs on their sides, but they are placed at different positions, hence making them very different.
The 1x2 modified brick w/studs on the side has 2 studs positioned slightly above the studs present on the 2x2 modified plate w/studs on the side. This means that when plates are placed on the 1x2, they do not sit flush with the base. The 2c2 on the other hand has its studs arranged so that the plates attached will lie flush to the base.
This seemingly small gap is important to know when using SNOT techniques, as you might want the plates you are attaching to lie flush to the base, or you may not. The best use of these pieces in my opinion is together; as you have a strong connection that lies flush to the ground.