i got 7TH in gardens (and 7Th at my friend farm) i will share myopinion.

pros

They are very well designed.
They dont care about ambient temps.
They are quiet.
They need 0 maintance.
They are stable as rocks, hashing 24h/30d.
They are very reliable, one dead board of 96 so far within 30 days.
They are not complicated, there is nothing can broke and stops whole rig from hashing.
They are stackable, u can build very high tower
Support is great, very nice people. RMA is not a problem, if they trust you they will send you first.

cons

They are not beautyfull
They have no leds so you have to look at pi leds.

if your pi dies, replace, same with dead board.

compare it to cointerra or sp

Any tips on undervolting? soon will be time to do that.

btw i have custom rig of only 2 boards sitting at my desk with 2 silent noctua fans. looks nice.