You are right about the C-64 power supplies. I went through a few of them, myself. I remember ultimately getting a 3rd party model that was advertised in Compute or Compute's Gazette back in the day. They touted that it was far more reliable. I think it was pricey... I have a weird memory of it costing $35 back in the 80s. (My grandmother was kind enough to spring for it.) I still have it to this day and it still works like a charm, so I guess it was worth the money. :-) Solid and sturdy... unlike the stock ones that came with the system.
On the other hand, you won't get me to easily praise much about the ADAM. heh I remember the commercials for it made it look great, though. Dragon's Lair looked quite good on it for the time! And it did play Colecovision game cartridges, so that was always a good thing. :-)