I've seen one of these on a spectrum analyser with my own eyes. Sprogs galore!
Recently found this interesting video and it seems some of them might be decent?

he is realy good

I’ve watched a few of his videos now and he seems to have the ability to buy some expensive equipment. He demonstrated a lot of transmitters and some of them are very pricey.

The 8066 i’ve got at 1w, the inband noise is not much more than normal desensitizing, with a match theres no danger of out of band spurs, harmonics were the same as max pro. If you wanted to use the full 5w you’d want to be further away from it, you'd want to put it in a box though.
You do get less inband noise on the bh chip ones, stereo is not as good as the 80 ones. 8027 is usally in the half a watt ones, puts out a smaller duplicate signal 12mhz above or below the main, hard to filter out, the inband noise is 4 times that of the 8066. The stereo is best on the 8027 I have, it doesn’t have a display, they scrubbed the markings off the chip, i’m guessing it is the 8027, from the duplicate carries and mondo noise, I mostly just use for listening to stuff in bath, so its not bothering anyone.