@donsachs mentions the Bottlehead kit as an option for DIY enthusiasts. I would like to note for those of you whose budget won't allow for the purchase of a Raven, and are willing to take on a DIY project, you can purchase an Audio Note Kits (ANK) L3 transformer coupled preamplifier kit for about $2,500. This will introduce you to the benefits of a transformer coupled output as @lynn_olson references above. These kits use very nice parts and are relatively straight forward to build. I myself built the L5 Mentor, and when you look at the price of that kit, it's right up there with the Raven which is sold as a completed build. Which goes to show the cost of the Raven is not unreasonable for what you are getting. In fact, I would have expected a preamplifier of the Raven's level of quality to cost more. So cost wise if I had to do it all over again the Raven would be a serious contender for me.
Personally, I find the tonality and subjective realism of transformer-coupled vacuum tubes to be unmatched by other technologies, but that’s just me.
While I like my L5 Mentor and enjoyed building it. I now use direct coupled preamplifiers and amplifiers. No capacitors or transformers at the output. Which is where I would stray from the comment from @lynn_olson as well designed direct coupled components in my experience take the tonality and realism up another level.