Thanks everyone for the very helpful input. +Ts all around.
This is exactly the kind of info I was looking for, in terms of build quality, customer service, ease of use, sonic qualities, use with km184 mics, etc. I do like the form factor of the MixPre a lot, along with the 1/8" output and the low noise floor that it's reputed to have, but I am wondering if the Mini-MP may work better with my mics and the types of venues I frequently tape in (not the greatest acoustics).
Think I'll grab whichever one I can get my hands on first and then if I'm not thrilled with the results I'll sell it and try the other one.
Any thoughts of other major brand preamps to consider (for use with R-09)?
Thanks again to all.