I did an extended audition on Boulder 508. The sound is superficially enticing but I tired of it. It lacked depth, image and realism. It sounded a little 'digital'. Good digital, but digital.
I bought the van den Hul Grail after an audition of more than a month. It costs a lot more but is worth every cent. Superb presentation and uncannily quiet. It is a match for all else regardless of price and so, in its way, is a 'bargain'.