This episode was really great. What makes this episode so great imo is that the writers didn't gave away what really was going on, so the viewers would only knew as much as Ash and co with all the uncertainties.
When they found the pictures that looked a lot like Brock, that was a bit creepy indeed. And not knowing what Lakoko/Ninetales was up to, added a really mysterious mood.
DP had a sorta similar episode, but the writers dumbed that one down which made the episode really predictable and less enjoyable compared with this one.