Warning: Do not rent rigs from coinminer, you will can scammed and betarigs doesn't care
Rented a couple of rigs from coinminer. His rigs behaved completely unstable with hashrate going up to advertised, then back to 0, back to advertised etc. He then claimed that his rigs were running fine and that my pool was unstable but this most certainly couldn't be true because other rigs from betarigs were completely stable. Only his rigs did this weird wave pattern in hashrate and all of his rigs did it (they even did it in sync some times). He then proceeded to sent me a photo to 'proof' that his rigs were hashing properly:
http://i.imgur.com/zRG8hrB.jpgAs you can see it's set up to mine at multiple pools which corresponds with the behaviour of his hashrates. When I filed tickets for the rentals betarigs blamed it on my pool despite all of my evidence that it was clearly not pool related and even told me that I shouldn't have posted such bad reviews for his rigs.
So I'm just warning everybody here: If you're renting a rig from coinminer you'll get half the advertised hashrate at best and betarigs will choose the side of the (scamming) rig owner.
You're right - coinminer has a lot of negative reviews mentioning the same issues. It's not just you... a lot of renters are complaining about the exact same issue along with the bad/unprofessional support. Look at the comments here:
It really sucks to bad rigs stay on Betarigs for so long.