Hi the AMB are the ones to go for, if you have a lower budget then go for the older type(as per the first ebay listing in the thread) they are good and will work with RC2/3/4 as will the 'Harry', but the 'Purcy' will only work on RC4.
I will have some brand new 'Harry' pt's for sale early next week, they are brand new from BBk as a part exchange deal I have done.
Watch out on Oople next week for the bargains
I also have some of the older type ones for sale £43 posted. Paypal gift or buyer pays the fees.