I've been coming across this advertisement from time to time browsing. Claiming people like Beeke and Paul Washer recommended it.
The Puritan Hard Drive (now $350, was once $800 and even under $300), by Still Waters Revival Books (SWRB), is said to have tons of great books and audio files. The special remark is the search tool. Which can search the whole library (160 GB on a portable hard drive) including pdf files (unless the language is old orthography). Instead of search, it is actually using a master index database and is said to display the highlighted passage of the keywords from the particular page of the particular book. This would definitely be a plus.
I've looked through the names of authors included. Very impressive, very promising. From Stephen Marshall to the most famous ones.
I can easily disregard some complaints, but the price is still a little bit steep for me. Perhaps I could work out a deal with them or wait for some future opportunity.