http://www.mtp-ums.net
it is "converting" - after that, it is like you bought player in Asia/Australia - you can update it only by official UMS firmware... so there is no such thing as "stability issue"...
each new firmware has 2 versions - UMS and MTP - ther are identicall BUT with one of them player is seen as "audio device" and requires winXP+SP2+WMP10, and with another as normal "disc" with any OS...
and yes - you can drag-n-drop songs with MTP player - it is still seen in "My Computer" as an "audio device"... WMP10 is required, but if you wish, you can never use it (it just "needs to be")