They are a Polish exchange so that could be why you have not seen much of them. Your best bet do your own research and make your choice after that has been done. Also you should check all the fee's to see if after they have been paid it is worth your time to try arb.
I think you are confusing BitBays.com with BitBay.net.
Regarding BitBays.com, I'm interested in the arbitrage fund, but cannot find much info (in English) online, so I'm reluctant to take the risk yet.
It appears that the arbitrage fund fees are low - no ongoing fees, just a 0.02% withdrawal fee (from the fund, not the exchange)
I'd also like to hear about anyones experience with them.