It used to be that two speed pumps were cheaper to buy than variable speed pumps. However, the new variable speed pumps are competitive with two speed pumps. Two speed pumps use induction motors, which use significantly more energy than a vsp pumping the same gpm.
Variable speed pumps use permanent magnet motors, which are significantly more efficient than induction type motors.
Variable speed pumps can be tuned to the exact flow rate needed with no waste. Two speed pumps rarely have the right high and low speeds for a pool.
Variable speed pump are usually very quiet. However, some have an annoying whine at certain speeds.
In short, I think that a variable speed pump can be a good choice.
If you're looking for the lowest cost in pumps, I would consider just a 3/4 hp basic pump.
If you have a short season and low electrical costs, then investing in a vsp would only make sense if the quietness of the motor were a big concern.
The Intelliflo is a good pump. However, in my opinion, it's overpowered and overpriced for most residential applications. In situations where I would choose an IntelliFlo, I would use an IntelliFlo XF.
