Spalding,

look for AJ's posts from about 8-12 months ago: he was actually asking members on this forum what would be a good compromise set of features for a lower-end arranger, and then he announced the SD5. Although it is mainly a repackaging of the selected SD1 technologies, it also has some new features and larger polyphony. Overall, I think this was a good attempt to produce a mid-level arranger (though my concern about price still stands).

Indeed, SD1 is a fairly old instrument (by today's standards), having been around for 4(?) years. However, Ketron has been pretty good issuing software updates which significantly improved the instrument over previous versions; they have even updated the sound set. Many times I have seen the manufacturers advertise instrument as being software upgradeable, but then these software upgrades are just bug fixes of the things that should have been working from the start. So in effect, this is just a way to turn the user into a beta-tester. While initial SD1 patches were all correcting bugs, some of which were fairly serious stability problems, the later software updates went beyond that. I wish Roland had done that with my G1000.

As far as completeness of the instrument goes - we all have different needs, and yours may well be different from mine. I need high polyphony and abhor heavy weight of the likes of latest Rolands and Korgs. Playing mostly live, I don't care about recording with the sequencer. Whenever I need to do a multi-track recording (which is very rarely), I am at home near a computer, where even a $60 PowerTracks provides loads more functionality than any built-in sequencer. I can see how someone else may want an all=in-one instrument, and don't care about the weight. This is why it is great that there is more than one model of an arranger on the market, and we have the freedom to choose, instead of being confined to a single one.
Regards,
Alex