Yea certainly initial indications point that way.
The stats show on honest Wargamer has then at a 69% win rate atm which whilst early days indicates they're pretty powerful.
I've had 4 games atm with a few different lists so only a small sample size but they've performed exceptionally well for me and I'm inclined to agree they are very good.
My concern is the mortek guard that are supposed to be tanky and do a great job on a 3+rerollable, but are also very, very punchy as well. (I charged and just took off gordrak before he attacked last week)
I do think people will learn to play against them and the meta will shift to adjust, but my impression is that they're fantastic and I've not come close to losing yet (I don't think this is my ability, although I know how to play a little)
I've run 3 lists so far and all seem very good, I think you'd struggle to write a poor list:
nagash with 2x10 Deathriders, 20 mortek, boneshaper.
Katakros with 2x10 Deathriders, soul Mason, 40 mortek guard, crawler.
Katakros with Soulmason, 2x40 guard, 10 guard, crawler, mortek shield corps, carrion.
Interested to hear what people are struggling against, I think maybe missions like 3 places of power or ones with 4+objectives?
Rich