Three months ago, hands down, why even argue, the answer would have been the PCM sound-equipped one sold for a song at Factory Direct Trains...in my humble opinion. Now, I wouldn't be surprised if it's a toss between the Riv and the Athearn, although I have never seen either run. Reports about the Athearn are generally very favourable in terms of running and looks...it's just that gosh darned MRC excuse for a decoder.
I believe, by the way, that Trix/Marklin are one and the same, with their collective BB falling under the Trix banner, and the PCM/BLI falls under the PCM banner.
The Trix should be a close second to the PCM in terms of looks and pulling power if the Model Railroader Magazine review is to be taken at face value. Its outstanding deficiency that I recall, except for perhaps the sound files on the Loksound decoder (?), is that the drivers are too low...their diameters are at least 5-6" less than those on the real BB.
My suggestion, as much as it'll cost ya, is to add a motive decoder to a Blueline from BLI. Otherwise, if it is advertised as a metal body, it is all PCM pedigree. What's not to like?