>>45033162Being immune to a type is always good anyway so all forms enjoy Levitate, though Rotom-Heat on paper as the best compatibility as you said with it. But with Mold Breaker Excadrill/Haxorus, sometimes Rotom-Heat wasn't the best choice too so it depends on how the meta evolve.
Still, Water and Fire forms are probably the best ones, with Grass being almost as good : it also depends on the team you are using and the play style (Singles or Doubles).
Fire was (before the bans) way more used in Singles because it would check Cinderace (like the Water one) but can also counter Rillaboom who was predominant in the format too. It is still used a lot in Series 6, being still in the top 10. The other two forms are also used a ton though, with Rotom-Mow even being sightly more used than Wash now.
In Doubles, Rotom-Wash was used more than the other two and is now used even more with Rillaboom's ban.
The other two forms are meh and really specific. Special mention to Rotom-Fan though who find some usage in Doubles and can technically do interesting things.
So, depending on what you prefer playing, Singles or Doubles, you might want to choose Heat or you might want to choose Wash.
