Ignore them get it if you want it
If you want the BD get the BD. Get a Corally. A used one from a 1/12 driver or something will do. They're all going for integrated rx boosters. Check oople and RCtech for sale, you will find one, and it will be a bargain. Its not a problem used. The build quality is first class.
But if you think you need the BD to have the fastest car on the straight, think again. The reason BD drivers love this speedo is the feel. That's why its quick. Even lacking a bit of top end on the straight with the old software I am still faster with the BD than with my other speedos, I have most of the others.
But its definitely much closer than it was in the past. You may laugh but the Hobbywing is easily a match for anything out there, feels good, massive top end and costs next to nothing. So there you go.