I use the SOLO mining feature, as it seems post-halving you'd need pretty near 5cents or less total kWh cost to slightly profit at current prices.  My power is 22cents per kWh so I'm not even close really.  I don't run my older Apollo BTC (1st model) currently because its even less efficient, but I will maybe in the winter when I could use the extra heat. 

I'm getting 5.85 TH/s (32 watts-per-TH/s) on ECO mode, I wouldn't want to run it higher than that because of the noise.  I get about a 1/700,000 chance of mining a solo block in a day with just the Apollo 2 in ECO mode.

My only complaints with it at the moment are:  software's still pretty early, missing a lot of needed features in the web GUI (like even individual control of the Apollo miners) - had a lot of hurdles in the setup, having trouble getting RDP into the full linux GUI (Ubuntu/Gnome) to work still. Node and miner aren't that stable so far, one or the other seem to hang or crash every other day or so, so far - hope that was mostly during, and due to, the few-day blockchain sync, though it has happened a couple times since then as well.

HDMI output and WiFi on the Apollo 2 are not great so far, really hoping those can be majorly improved compatibility-wise.  None of the monitors I have at the moment work, and the wifi is very finnicky and you need a separated 2.4 GHz network for it (basically, not a modern wifi setup, at least as most come by default these days, like using a single SSID for all wavelengths, etc)