Almost all Liliana planeswalkers have been historically very valuable, and it looks like the Dreadhorde General is not an exception either.
All of her abilities are very strong, and this card can be used in almost any type of deck and format. Usually, such powerful universal tools hold up really well on the market, and this one may get even more expensive in time.
The ultimate ability can finish games quickly, and it won't take much to get there, since Liliana already enters the battlefield with six counters. This means that three turns later you can blast all opponent's lands but one and say "Good game."