Apologies if this is a stupid question...I have searched around and I am not finding anything.

I have an RX580/570 farm on HiveOS.  I want to mine the most profitable option.  I am a bit above breakeven given my power situation.
On whattomine.com, AMD cards get the best profit on Nicehash.  I used to mine ethermine.org but decided to try nicehash.
Occasionally...like every few hours, my whole farm goes down.  It appears to be because the nicehash pool is not accepting connections for a few minutes. It will then resume.

My questions: 
Do you think nicehash is the most profitable?

I am staying with HiveOS for sure....I love it...but is the way I am mining through Nicehash the best idea?

Do you know why Nicehash connection goes down so much?

Thanks for your help!