This Really Depends on the quality of the electronic drum kit your are buying, the thing you should look out for the most is how responsive the heads and cymbals are. I've plaid some shoddy electric kits in my time where it is delayed from the time you hit the pad to the sound playing it is very minute, the timing delay but for a drummer, the timing needs to be perfect or you risk going out of time with the song and so forth when in practice. Also there are naturally things an acoustic kit can do that an electric kit cant, like choking cymbals and performing rim hits.
The most obvious of differences between Acoustic and electric is the time in which it takes to set up as well as the space in which it takes up. also you wont annoy your neighbours quite as much with electric. But you get a much more authentic and better quality sound from acoustic. the maintenance of an acoustic set requires ALOT more attention. But the cost of electricity is increased with electric. Overall Acoustic is a lot more expensive. the sticks wont degrade half as quickly with electric sets and the heads arguably last longer than the skins for acoustic heads.
If you are buying second hand check the quality of the wires as they can stop the drums working completely. each head has a separate wire. Also pay very close attention to the sensitivity of the foot pedals I once tested a kit that doubled and even tripled up strokes on the hi hit foot pedal so when I pressed the pedal once it hit twice and three times and wouldn't clamp down as a closed hi hat. the springs also in the foot pedals need to be checked for rust and so on. Do not be fobbed off with faulty equipment, test it fully before buying it. things are easily covered up with electric drum kits in my opinion.
I am editing as things spring to my mind here but also do not leave either kit (Acoustic or Electric) in damp areas, it can take no time at all in killing either. the wires and electronics are a lot more susceptible to damage than on a good hardy shell of an acoustic with its metal stands and clamps but springs in the adjusters of the acoustic kit can also rust making it a pain to adjust them. plastic makes the electric kit easier to adjust and set up.