I would agree with DEP. The Pass Lab preamplifiers are great. Just a couple of months ago I upgraded to an XP-32 from an XP-22, and its the best preamplifier I have ever had to this point in my audiophile journey.
Great tonality, resolution, dimensionality, and speed without the tube hassle.
Using it in conjunction with a 350.8, and am very happy.
In terms of the 150.8, Steven Stone has one in his stable of reference amplifiers for reviews. The fact that he has kept it for a few years should say that, at the very least, the amplifier isn't horrible.
In terms of reliability, customer service, and (because the audiophile itch gets to us all) good resale value, I don't think you could go wrong with the 150.8.