I did not do a compare but I believe when I first got it a few days ago it actually increased the number of devices that were working, then a couple days or so I had major zwave device issues and once restored I noticed that a large number of devices, mostly Zigbee, were reported as disconnected in the new app. In the classic app these devices were reported as working fine… and in some (all?) cases, the devices also worked in the new app if you opened the device page and interacted with the device there. Anyway, I was bothered by all the disconnected tiles so I did a couple things… I cleared the app cache (only the cache!), and I powered down my hub for 10 - 20 minutes. The latter is the method to cause ZigBee devices to panic and try to find a new path to the hub however I likely did not need to do this as those same devices were working fine in the classic app. Anyway, long story short, everything is back to normal.
The above only fixed the numerous devices reported as “disconnected” by the new app. The other issues, such as screen resorting/jumping around while you scroll or trying to tap a tile have somewhat improved but not fully fixed yet. Add the multiple tapping before a selection actually responds to taps (I have a Note8 and this is the only app that does it) and I too cannot call myself a happy camper either, but I do see progress so trying to use the app more and more.
To get stuff done quickly, however, classic is still way ahead for one big reason… the rooms/groups screen!!! The new app has that horrifyingly long dashboard screen that is anticipating my index’s arthritis by a decade… 22 screen flicks to get to the bottom of the list (and I have hidden lots of devices!!!) - what UI designer can possibly think that is acceptable? Sure if you design this for users with 15-30 devices, it works… GRRRRRRRRRRR this always ticks me off!