I've used one of these for the last couple of years with no major problems...

http://m.ebay.co.uk/itm/250868555905?nav=SEARCH

Easy to set up with phone, can listen to music fine at low speeds, great for communicating with pillion, using phone or listening to sat nav... had to reconnect with phone a few times, but at �30 a pop you can't go wrong... you can get 10 of these for the price of one scala set!