Based just on what I read about it I guess the ready to go box makes sense for a very small niche audience but It's not something that I'd use. The reasons that I'd hesitate are that it's a single tasker with limited expansion and I'm not seeing any built in redundancy such as some flavor of RAID. I'm sure you could figure something out but that defeats the plug it in and just feed it discs idea. In my opinion redundancy is a non-negotiable checkoff item when looking into any solution and when you're dealing with hundreds or more likely here - thousands of CDs. I prefer double redundancy (RAID and backups) just so I never have to re-rip after a drive failure. On the other hand maybe running the software on an old PC might be a decent solution as long as it supports RAID1 or RAID5 and some form of automated backup.
I prefer to rip at a PC and then copy to RAID enabled NAS devices or servers (the original becomes a backup). dbPowerAmp fully automates the rippping, tagging, and filing of CDs
to your specifications and it's $38. Once you've ripped all your CDs you just run the included Batch Converter against the rips to create, tag, and file MP3s or whatever flavor your portable prefers. If you shop well you can pick up a power sipping RAID1 capable NAS $100-200 plus the cost drives of your choice.
Whatever solution you go with the two critical things to thoroughly think through in advance are your filing system and your backup solution. Re-ripping hundreds or thousands of CDs because you didn't do due diligence in advance is an experience on par with a root-canal.