The BU500 is nice, but it has (at least the 2 i bought) a problem powering up if the supply voltage is a rising at power up.
I solved this issue with a small relais which switches the voltage on to the BU500 with a small delay when the voltage of the psu is stable at 12V.
The amp inside the BU500 could generate about 2W without problem but the bandpass filter is designed for 500mW max. So be carefull.
It could be a good idea to remove this bandpass and use a good lowpass after the main amp.
Also i did not get the "programming software" with the BU500 to change the LO frequency, but it is preset for 430MHz and thats fine for me.
The other specs and measurements of the BU500 are all good to excellent.