If it was cast by Garruk's controller, he or she can choose which one stays and which one goes to the graveyard.) (Note that as Clone enters the battlefield as a copy of Garruk, it will have 3 loyalty counters, because that's a property of the Garruk card.) It was possible to have Clone remain on the battlefield even under the old rules, but it required a much more contrived set of circumstances
As with any TCG, there are different play styles that lend themselves to your personal preference and help you enjoy the game
A deck that focuses on sacrificing creatures for value, such as a black sacrifice or aristocrats deck, would benefit from using Lolth, Spider Queen
Lonis, Genetics Expert They (surly) forgot a once per turn rider on the evolving Lonis, Genetics Expert, which makes this combo city if you want to build it that way
However, of the slivers of that era and class, this is the least played and most powerful