None of my stand mount speakers are going anywhere without the stand accompanying them. I use three good sized blobs of blu tak under each one - think ping pong ball size.
What you will find is that over time the consistency of the blu tak changes from being relatively easy to keep in a ball to coming off on your hands a bit. I do suspect that's exacerbated by our dry hot climate in AZ, but eventually this happens everywhere.
Surface residue is somewhat dependent on the surface. The black piano gloss on my LS-50's is pretty impervious, whereas matte and light colored surfaces will be more inclined to show after a period of time.
All in all, I find blu tak highly preferable to screws or spikes and more effective than using grippy rubber type sheet product for coupling. Some folks want to go the the way and de-couple, but that does leave stand mount speakers vulnerable to accidents.