Topspin or slice backhand?
Many tennis players have problems with their backhands. Since there are many techniques to choose from - double-handed, one-handed slice, one-handed topspin shot - they keep experimenting with their backhand, which doesn't do them much good. I'd like to put a few fundamentals together that should help you make the right decision.
You may have noticed that when I listed the techniques, a straight backhand or "drive" shot is not on the list. There is a reason for this - because in reality, this shot is almost non-existent. Your backhand ball will have either forward or backward rotation 99% of the time, and you should always make a clear decision which way you want to go.
There is nothing wrong with having only a slice backhand. The vast majority of tennis players in the world do just fine with a slice backhand, as long as they understand the limitations of that shot (see below).
When you play that backhand slice, do not try to hit the ball too fast. The slice shot must be a controlled shot - it should have high precision, but not high speed. Remember that even a slice ball that travels at a relatively low speed will be difficult to hit back if it does not bounce too high, goes deep in the other players court and is well placed.
Having a topspin backhand in your arsenal is a very good thing of course. If you can do both a slice or topspin shot, you have a big advantage. But you will never be able to hit every ball with topspin.
The topspin shot requires a solid balanced position, you will want to hit the ball at a height somewhere around wait high and you need to have enough time to build up a high amount of body tension. But in a match against an equal opponent, the situations where all those conditions apply may be somewhat limited, and you will find yourself using the slice pretty often. It would be a mistake to ignore this technique, or to try and use the topspin shot when the situation does not call for it.
If you can do both the shots, it is important to make an early decision on which technique you want to use in a specific situation. I would suggest that you use the topspin shot when you want to put pressure of the other player or when you want to hit a winner, or when you are in a desperate situation. For a passing shot, the topspin shot is better most of the time because of its higher speed, and because sometimes you want to aim for your opponent's feet.
You should use the slice shot when you want to go for consistency (assuming that your slice is more consistent than your topspin), when you are late to hit the ball, or have bad balance, or when the ball bounces very high or very low. And then there is one situation where the slice can be played very aggressively: when you can hit the ball very early from inside the court, thus not allowing the opponent to re-position himself in time. For a topspin shot most of the time you have to wait a little bit longer until the ball has fallen down to the right level. That can be made up by higher ball speed, but very often hitting the slice early and with lower speed can produce a better result and put more pressure on your opponent.