Metrum octave vs new Rega DAC vs Eastern electric

Have you tried discrete opamps in your minimax? Since you like a meaty/rich sound I would suggest trying Burson opamps. It will cost you about $200 but IMO greatly improves on the stock sound.

Of the two other DACS you mentioned, the Metrum NOS Dac has received a lot of accolades from board members and the price is particularly favorable now given the $/Euro conversion rate.

I have not heard the EE but have had both the others. The Rega is quite good but the Metrum is better. A friend who mostly uses vinyl was over today and said he liked my digital front end even better than my vinyl; something he has never said before.

Metrum is in a completely different league than Rega. HiFi Critic awarded metrum with 170 points, and Rega with ... just 50. That should give you an idea about the diferences we are discussing here.

One word of advice though - the Metrim is very sensitive to signal jitter. Buy only if you can afford to buy an Audiophileo 2 USB->SPDIF converter ($579) to go with it. Cheaper converters, like MF V-Link, Stello U3, HiFace 2/Evo, Halide etc will not do it (yes, I have tested them all with Metrum and then some).

Coupled with Audiophileo, Metrum is absolutely stunning piece of gear. You can pay 10x more and get lesser sound.

Get the Metrum. You are getting a dac that competes with much more expensive dacs. I find it sounds great with a Halide Bridge, or from my Squeezebox Touch with the enhanced digital out. Haven't tried the Audiophilio, but I probably will.
The Metrum is pretty much without a sonic signature, but very musical. That is what I want from a dac.