All of this has been an interesting discussion. I've enjoyed the ideas put forth by those who claim experience in this maneuver.
Let's take it one by one. First, the tactical aspect. There is no tactical advantage to be gained by the 'tail slide'. Those that think so may be confusing the maneuver with the 'hammerhead'. That maneuver had some applicability in a guns only environment...but in a heat-seeking missile fight, not a particularly good idea.
Now...'tail sliding' in the F-4...in a knife fight. Not really something we did much of...this result of an excessive nose high pitch attitude was the mark of a true rookie. Instead, in a vertical fight, we often got into a 'who can fall the slowest' type of fight...essentially either a very slow rolling scissors or a flat out full aft stick, rudder walking exercise on nose control. If you are still with me, carry on.
Aircraft, being often much smarter than pilots, tend to want to keep the pointy end going forward. For that reason, once airspeed has slowed to zero, the entry into a 'tail slide' usually results in the airplane pitching one way or the other towards the nearest horizon. The aircraft then sorta flops around (goes thru a few nose low pitch oscillations around the true vertical) for a moment or two until it gains enough airspeed to allow it to once again fly pointy end down. At that point, the pilot is free to begin his recovery procedures.
Lastly...aircraft do not 'spin' when coming out of a 'tail slide'...not unless the pilot is a complete hamfist.