I used a Mini Me for a long while. The coax is notoriously flaky on it. If you have doubts, do a search on this board, you will find plenty of people that have reported similar problems. I only used it to patch out and had a high rate of the thing cutting off a signal after locking on. Some people have had a new connection soldered on, so maybe look into that route if you want to use SPDIF. Personally I just liked the locking connector and reliability of AES and never had any problems going AES>312>JB3.
As far as battery life on the Hosa goes, it is great - but it still requires a battery.
My advice would be to use a 661 if you want a digital in on a small, relatively cheap recorder. And if you want to make complete recordings on a stock Mini-Me going digital out to your 661, get an AES>coax SPDIF cable and forget about the coax out.