It's not exactly the same -- these readers (and many other color e-readers released in the last decade) use a different type of e-ink panel, likely Kaleido. Kaleido has much better color resolution & depth, and shorter refresh times than the ACeP panel from TFA. However the con is that the colors look much more washed out and the display has less contrast overall and even limited color viewing angles. This is because Triton/Kaleido panels use color filters like any other LCD instead of actually having colored pigments like ACeP. ACeP is the only color e-ink panel I have seen which truly impresses a bit -- if you can stand the obscenely long refresh rate.
You're absolutely right. For 'old magazines', as per GP, it's probably just fine. I've no idea about how manga would fare.
There's some youtube videos that give a hint of colour reproduction - and yes, both those models are Keleido - and while they're certainly nowhere near print or LED quality, for most of my purposes I reckon they'd be a more than satisfactory replacement, especially given the benefits.
