That is my referral link to sign up to MRR yourself.
The profitability compared to nicehash depends on what you set your rental price at.
And yes, you can lower the price if you like, MRR even has an option to automatically adjust it to market value.
Personally, the value of being able to alter where my miner is pointing when I want is worth a bit of a premium.
I use nicehash and zpool when it is not being rented out