I haven't used them but I seem to recall them having a higher failure rate. Also there was something weird with their firmware, they were actually banned on Kano.is pool. I can't even remember what versions of miners we've actually seen released. If you check
The Current Competitive Hardware thread you can follow their links or look into other equipment, that is more efficient and powerful.
https://bitcointalk.org/index.php?topic=1737602.0This is probably the best thread for you to read through and post to get some information.