I shall undelete one link which is definitely on-topic.
hey, Can you tell us if you earn something?
Can you cashout?
How many profits?
In this often-updated thread on investment forum in Russian (google link #2 on btc-arbs)
http://mmgp.ru/showthread.php?s=d909ba6b7d585787edc154225da5a94f&t=246426&page=19they keep their eye on the "health" of the service. It has 19 pages up to date.
They have run into no problems so far.