I found the internal database did have a suprising number of reasonably obscure English folk / trad CDs in it, but the failure rate on my collection of French, Italian and Scandinavian CDs was pretty high.
The solution I found was to rip the CD on my computer using Windows Media Player - the hit rate on the WMP database was considerably higher than the Brennan one, and when it does still fail to find a match it's exponentially quicker to input the details on a computer keyboard than it is using the Brennan's [otherwise excellent] controls.
Make sure you set WMP to rip the CD into MP3 format and at a reasonable (192 or higher) bit rate. You might also want to experiment with the filenames created by WMP until you get the best results in terms of displaying the album & track names on the Brennan.
It's then very straightforward indeed to copy the folders of MP3s created by WMP to a USB stick or drive, and then connect that to the Brennan using the USB port on the front and import the albums using the USB functions >> Transfer Albums facility (I think it's called that, I'm not in the same place as the Brennan at the moment).
Other systems are indeed available but I found that the Brennan IMNSHO provided the best features / convenience / sound match for our needs, and I've certainly not been disappointed with it (and at least one friend has heard ours and & bought their own!) Ours spends 99% of its playing time on the Random Play function, and just like the advert says we've rediscovered all sorts of wonders we'd forgotten we'd got ...
Two very minor niggles - the remote control button layout seems a bit random; and the system is supplied defaulting to 'blending' the end of one track with the start of the next, which is very annoying but also very easy to turn off in the system settings (and once turned off stays turned off). Other than that it's a brilliant bit of kit!