There are many different versions of C150s. Engine and propeller differences are what you are seeing. Read the manual for the particular aircraft, it may have a climb prop which may require as much as 2400rpm for the cruise. It should cruise at about the same speed as a C152, within about 10MPH.
There can be different flap deployment methods, a big lever, a hold down electric switch or a set and forget like the 152.
Most have 40 degrees flap with which you should use caution 'till you know what to expect.
It may also have different stall characteristics due to wing section, tail and tip design.
The list goes on. Read the manual.
The early straight tail ones were particularly nice.
DO.