I purchased one of each, the Vastelec FM01 and a Vastelec FM02. I built dipole antennas using RG-58/U (left over from the ol’ 10Base2 Ethernet days) and both transmitters work flawlessly.
It is extremely critical that exactly 12VDC of perfectly regulated power feeds a Vastelec transmitter, a lower quality regulated wall-wart won’t do - the hum will drive you crazy. It’s also very important to use a shielded stereo cable between the computer sound card and the Vastelec transmitter, using a standard speaker cable will pick up noise from Mars. I have balun chokes on the power lines and on the antennas.
At one house, I use the FM01 transmitter almost year round, playing my own tunes a good .5 mile in all directions. The FM02 runs at my other house nearly every day of the year but with its elevation I can pick it up nearly a mile away. Stereo separation is excellent with either transmitter.
Neither transmitter offers RDS, which is fine with me, I’d rather have folks watching the blinky-flashy and not reading their radio.
joe