An immersion blender moves into a suitable vessel; a countertop blender brings the food into its own jar. That difference affects batch size, transfer steps and cleanup. Before comparing power numbers, decide which arrangement suits the meals you make.
For a soup or sauce, an immersion blender may reduce the need to transfer food, but the vessel must be appropriate and deep enough for controlled use. Follow the appliance's hot-food permissions and operating instructions. Keep the blade guard positioned as directed and avoid lifting a running blade through the surface where it can splash.
A countertop blender provides a dedicated jar and lid, which can be useful for mixtures suited to its design. It also means transferring ingredients into the jar and washing that vessel afterward. The permitted ingredients, temperature and maximum fill depend on the model.
Hot food requires explicit permission
Never assume a sealed personal blending cup can handle hot liquid. Heat, steam and pressure can create hazards in products not designed for that use. For any blender, use the specific instructions on cooling, venting and lid placement rather than copying a method from another machine.
Immersion tools also have limits. The shaft may have an immersion line, and attachments can have different permissions. Keep the motor unit away from water and unplug before changing or handling blades as instructed.
Think about texture and quantity
A small amount may not reach the working area of a large countertop jar. A thick mixture may require a different machine or a particular loading method. Look for the minimum useful quantity and supported tasks instead of assuming more wattage means every texture is possible.
If you want smoothies in a portable cup, a compatible personal blender may be convenient. If you regularly make larger mixtures, the jar shape and capacity deserve more attention. An immersion model can be easier to store, but attachments may quickly expand the footprint.
Choose around the task you repeat most often and the parts you are willing to clean. One well-matched blender is more useful than a collection of accessories that almost performs several different jobs but never feels straightforward.