Yes, in doubles I would say that the topspin is better on defense than the slice unless you've got a good slice lob. I just instinctively was talking about singles.
But I'm saying even a good topspin shot is going to bounce higher than a slice, and it's going to get to your opponent quicker. When on defense, you need to buy yourself time, and you want to avoid giving your opponent another good attacking shot. Mediocre topspin and slice shots can both be returned easily offensively, but I think most people are more comfortable returning a solid topspin shot (hit from a defensive position) in an attacking manner than they are returning a solid slice in an attacking manner. That, combined with having inherently more time to recover with a slice, makes the slice superior in a defensive position. This is assuming you can hit both a slice and a topspin shot adequately from this position, and again, in singles only. If your opponent is a net rusher I would go topspin, but most people these days are not, so I go to the slice first and think the majority of the time it will be more effective.