While motoring up the Guadiana River (border of Spain and Portugal) several years ago we passed an anchored junk of probably 35 feet with a radar scanner mounted on a pole on the bow. I have a picture somewhere but it 's not accessible at the moment. There was never anyone on board to chat with. I mentioned it to Robin Blain when I got back to the UK and he knew the boat.
I imagine the scanner's forward view would have been fine, but the foremast - alloy, I think - was pretty close behind it, so I guess the rear view could have been marred. Like you I've never had radar (only 'needed' it maybe three times in 30 years of summer sailing), so I don't know if the latter observation is correct. Having it up front seemed a better option than on some kind of stern pole or gantry, where I'd worry about it frying brains, though loads of boats in the UK have them there.
Our Freedom's sails have ended up well below the mastheads, so were we to fit radar we would have the option of attaching the scanner below the mastheads, where Freedoms often carry them anyway, the masts being carbon fibre. I don't know whether to do this, though. I suspect I'd rather eat the money.