Over the past 6-12 months I have been incredibly lucky about being in the right place (cyber-place not physically) at the right time and have managed to trade or buy my way through to an extensive set of old blue modules. It’s funny playing these older system modules vs the newer ones - there are clear differences in Tom’s approaches and thinking between then and now, layout and ergonomics being the obvious point, and refinement in terms of features and I/O - newer modules are absolutely no nonsense and a joy to play, the older ones generally have more cv I/O but require you to burrow through the cables to get through to the knobs 
I have found that the latest versions of the oscillators and filters are far superior to the old syn2a and prc3a, sonically they just feel lightyears ahead - smoother, cleaner, more present and more ‘alive’ for want of a better word. The new LPG smokes the old one too for functionality and playability - I absolutely love that it doesn’t require a separate envelope with the ‘hit’ function. However, I do prefer the old wavefolder with its greater degree of cv control and offset control, you can really spend time tuning in a perfect timbre for any given situation and it pairs with the new LPG like magic.
The old envelopes are basically identical to the new dual version. They are awesome.
I’m excited to see Tom bring about more new versions of old designs - the frequency shifter, bugcrusher, ring mod, quad sine etc - these are beautiful sounding parts of the old system that I think will benefit massively from Tom’s new ideas. I hope to try the new blue PT delay soon. I’m absolutely stoked for the fabled phaser to be finished too.
One thing I’ve never tried or even seen in the flesh is the old SEQ1 sequencer, but have read much about how joyful it is to use! I really hope Tom updates this design soon, as much as I enjoyed the DDSR I am much more of a ‘dial it in’ kind of guy than I am into chance and non-repeatability. Batchas’ le seq + expander do much to mimic the functionality and are really excellent compact solutions to this, but I’m definitely missing a larger format sequencer.
Anyways, ramble ramble ramble. I hope to make some short videos soon showing functionality of the more rare parts of the old system I’ve been lucky enough to obtain - there is really very little available online in terms of examples.
Here’s my current 3x16fw system:
