The only flaky ESP hardware I know of is the ESP-01, which was one of the first boards carrying the ESP8266. It's still available for about $1.50 shipped from A

The only flaky ESP hardware I know of is the ESP-01, which was one of the first boards carrying the ESP8266. It's still available for about $1.50 shipped from AliExpress. They're hard to program because each one seems to have a different opinion whether this or that GPIO needs to be grounded to start programming mode. They also can be poorly manufactured. Either the antenna is so bad it works on your desk but not in the next room, or it's just DOA. Fortunately, these are neonatal problems; if it works for 5 minutes, it'll work forever. And when you can get 10 for $15 and toss the three that don't work, it's still a great deal.