I think it was underpriced. The recent fork went well, and ETH was due a rise. It had never recovered back to its all-time high of around $400. Once it finally broke through that resistance, it was free to soar 
It's not just a short-termer though, ETH has the potential to be far far bigger than it is now
It's not just a short-termer though, ETH has the potential to be far far bigger than it is now
I know all ETH holders will be delirious but hold on to your horses just for a bit. Yes, it finally re-reached its ATH and broke free a little bit, but remember the last time it did, a lot of other alts like Litecoin did the same... more importantly, it was Bitcoin that broke ATHs and every alt took the same taxi.
Now, ETH is just reaching its old peak... while Bitcoin is worth twice what it was the last time ETH was here. So for ETH to really impress it either has to reach significant new ATH OR... it must peak when Bitcoin is falling or stable for a long time.
But of course, credit to ETH for surviving the fork.