Hi,
Origin is a great synth and it deserves a good controller for sure. It also has quite a lot of knobs itself so IMO the most important thing to check is the keyboard action. How does it feel when you play it. Believe me or not, how it "sounds" to you is also result how it feels under your fingers. Also of course you must decide how many keys you need. IMO 49-keys or more is what Origin needs. This is one reason I wouldn't take Analog factory keyboard with 32 keys. Another reason is that these controllers (well I haven't tested the newest line...) feel little cheap; I would like give my Origin little more higher class playing feeling.
Ok, what would I suggest then? I have Roland A-500 Pro and at least to my fingers it feels very good. It ain't the sexiest controller but it's really better to play than most of those Novations and M-audios etc. IMO Akai does also good controllers too; if I hadn't mine I would probably try their MAX49.
What I personally use 97% of time with my Origin Desktop (at home I use Origin Keyboard which is great too) is Access Virus Ti2 Polar. This is a nice couple and Virus has a great keybed (I think it's Fatar something...).
P.S. And yes, these are quite subjective thoughts anyway....
