I think a classic iPod touch wheel feels more polished, but the Tangara wheel is like 90% of the way there. In previous firmware versions the middle button was too sensitive but that was fixed. You can adjust the sensitivity but I find the default setting to be perfect for me.
I love my Tangara! I even made some custom themes for it. The regular ol’ headphone jack is perfect and it sounds great too. I wouldn’t wait for the Echo R1 unless you really need Rockbox or the different I/O.
I don't use one, but my partner reports it lasts a couple days of use (~10 hrs/day). I think that's with wifi turned off though. Not sure if this is with bluetooth or wired heaphones either