When you are looking to buy a circular saw blade consider the following properties:
Tip is the most important part of any circular blade as it cuts through the timber and should be strong enough to cut through hard dense wood.
Shoulders hold and support the tips so they can give the high end performance all the time.
Gullets remove material from the timber & with every rotation gullets remove a bigger chunk of material. For finer cuts, manufacturers also offer circular blades with shallower gullets.
Expansion slots are there to prevent the blade from warping as the material expands and contracts multiple times during the operation. They also help in providing a straighter cut while decreasing the amount of vibration so the operator can steadily hold onto the saw.