Wifi, no problem. If you have wifi issue, it will be your router / modem. Don't blame it on the machine.
Waste of cat litter, no even close. Just let it sit for a bit, and cycle at 10 mins. Or change your litter. I probably wasted more doing it myself
Those were the 2 reviews that almost stopped me from buying this machine but I bit the bullet and bought it.
It has been great. No waste litter. Wifi connection is stable at 2.4G. app is pretty good. The only complains I have is that I can only bind it to one cat.
I am getting another one as this is probably the best machine I have owned. I tried petkit and was worse. The open top of this machine made my cats feel free. They can stand tall and poop.