If your son intends to use the unit for his job, I would certainly recommend an Hi-MD unit, such as the MZ-RH1 (some are already available second-hand), because: - it is able to connect to a PC via USB, with no restriction on uploading / downloading (many (almost all) earlier models from Sony, such as the Net-MD models, had absurd restrictions on the data transfer) - the 1 GB capacity of Hi-MD discs allows up to 1 hour recording without any compression (i.e. for professional recordings) - it can read and record all MD's (72/80 minute format (the original MD) up to Hi-MD - also it can read from Sony data format (as all other models), but also the MP3 format As for the microphones, they can range literally from the equivalent of a Nissan Micra to a Ferrari. One of the cheapest models is the Sony ECM-DS70P (look on ebay, some come from China at absurdly low prices). One that has received generally good ratings for a reasonable cost is the SONY ECM-MS907. I hope this helps,