Just got my BTR17, on impulse, following a similarly impulsive spend on a KA17, haha.
I have already BTR7, BTR5, Q5S and a number of Fiio Daps (M11, X7ii, etc), all of which are still going strong. Oh and a K5 pro and an ageing Mojo.
On the IEM side, I am currently using some FA19s
I bought the KA17 as the BTR17 was not readily available here, and the actually it's a very impressive little bit of kit. Ample power and really excellent sound for a tiny device. BTR17 is equally impressive. Sounds very similar to KA17 unsurprisingly, but maybe I prefer the KA17, I don't know, the jury's out on that. I can't help but think it's placebo, as the KA17 just is such a cute little thing that defies it's capabilities given its size and weight.
I've been dabbling alot also with Roon and Roon Arc being able to use these bit perfect with my Android phone, which is great.
Relative to the BTR7, both these new gen DACs outshine it, quite literally; they sound shinier, sharper, more airy, more open. They tend to risk becoming a little too bright sometimes with the FA19s, but tweaking the digital filters and use of new complys has regulated that, no EQ required.
Briefly, recommend both the BTR17 and KA17 wholeheartedly, and perhaps, if you've less need for the BT aspect but still want a good cheap DAC, go for the KA17; it's just so good for the size and price.
Great fun DACs either wired or, for the BTR17, in BT mode.