I have been operating a GPU ETH mining rig since the December 2017, the total cost so far to build it has been $1,661. That's a lot of money for just ~ 58MH/s hashing power. Now, things were different back in December 2017, let's see how does it works out now (August/September 2018).

Building a 12 GPU Ethereum Mining Rig From Scratch - Part 1: Ordering Details

For most of the Summer my Ethereum mining rig has been powered of (because of unprofitable mining - high electricity price / low etheruem price)

Mining ethereum August 2018

 

Mining ethereum August 2018

I turned on my mining rig for 24 hours, and mined 0.00417899 ETH (with ETH changing hand at $276.18) that gives me about $1.15. Not bad, but let's see how much we are spending here:

Ethereum mining calculator

Ethereum mining calculator with 0.2$ per KWh

It turns out, I'm actually losing 0.4 dollars per day right now. Sure, I'm paying a hefty  price 0.2$ per KWh and I could move my mining rig to some cheaper location, like for example Georgia, paying just 0.1$ per KWh and in theory I would generate a small profit even now:

Ethereum Mining Calculator

Ethereum Mining Calculator with 0.1$ per KWh

Cheapest Electricity in Europe for crypto mining (Cost per kWh) 2018

Since December 2017, I have mined in total 0.54398387 ETH. To break even my base investment $1,661 ETH should reach $3.060 (hard, but doable). 

Last time I measured, the price for ETH was well above $5,000 (now, this is a great achievement already) 

To Break Even My GPU Mining Rig, Ethereum Should Reach $5,153

Now, answering on question is it profitable mining Ethereum now (August / September 2018) - it depends - it still is profitable if you enjoy cheap electricity, and it is if you believe ETH will appreciate in value in the future.