I can get the ASRock x470 Taichi Ultimate AMD Promontory for $230.00 US  Is this a good replacement board?

Thanks

Between the Taichi and the Gaming M7 there does not appear to be much of a difference aesthetically (similar color scheme). That said, the Taichi appears to have a significantly more substantial power design, comes with 10 gigabit LAN and better VRM cooling. 

The Taichi ultimate is a top teir X470 board, the Gaming M7 is not in the same league just comparing specs. This is not me touting ASRock's product here either, just the simple facts.

As for the GPU, the board brand won't make any difference at all. The only time one might see a slight benefit is if the board manufacturer includes a "boost" feature when a particular brand GPU is installed and all this would be is a light overclock that can easily be achieved on any board. If memory serves ASRock did something like this when they partnered with Sapphire a while back, you would get a neat looking "ASRock + Sapphire" logo at post and I believe you could enable a "boost" feature for a slight overclock on the GPU. Picking a board brand to match your GPU is only useful if you are trying to brand theme your build so all the logos etc match, functionally, it serves no purpose.

In addition to all this, your X370 Taichi supported your RAM well (particularly for a first gen board) so the odds are good that the X470 Taichi will as well. The same is not necessarily true of another brand/model.

All this is just my 2c. I am a Taichi user myself and have not a bad word to say about the Taichi branded boards I have used, solid, reliable and packed with all the features I could want/need.