I'm quite interested in Recordo pianos as well - not for any particular reason!
Bob Billings is the King of Recordo - I have his complete book of rollographys, including a huge 300 page volume on Recordo rolls and
In a nutshell, Recordo first appeared in about 1915, and in the early 1920s was offered as a 'generic' reproducing system, that any company could fit to their pianos and any roll company could produce rolls for. there were 3 types of system - the 'A' which was an early one, the 'B' which was most common and had 5 expression levels, and the 'C' which appeared late in the game and had 16 expression levels - apparently these 'C's could rival an Ampico or Duo-Art, with a decently-coded roll.
From what I read, the main 'problem' with Recordo is that there was very little standardisation from manufacturer to manufacturer, and this applies to roll makers as well as the piano makers. The Recordo system was implemented completely differently by each manufacturer, and the expression coding was carried out differently by each roll company.
I asked Bob a few months back whether there were any CDs available of a good quality Recordo piano. Bob replied that he didn't know of any, but kindly processed some of my Recordo rolls that I've scanned through some software that emulates the Recordo performance characteristics.
If you're interested, here's some of the MIDI scans - this will give you an idea of what the Recordo was capable of:
This one's a Vocalstyle 'Dinner Medley' roll from 1926, coded for the 'B' system. Bob commented that the expression coding was 'competent', but not particularly inspired.
A QRS master released by Mastertouch with Recordo coding. Bob commented this one seemed to be a compromise between 'B' and 'C' system coding, sounding a little too exaggerated on the 'B' and a little too subdued on the 'C'!
This one was an Imperial roll, again with 'B' coding. The coding is quite well done, according to Bob.
Another 'B' roll. Bob's namesake Robert Billings (1899-1985) did all the Recordo coding for the US company, and Bob and I both agree the expression coding is the best of the lot.
Of course, by now you'll probably be hearing the other main problem with Recordo rolls - you could put in far more expression coding yourself by using the pedals! However, I suppose they filled a niche as a poor man's reproducing piano, or a way those who didn't care to pedal could listen to 88 note rolls with a bit of expression on their electric player.
(Sorry for you having to copy/paste the links - BBcode doesn't seem to like URLs with brackets in the filename)