The Sequel offers more tire clearance and thru axles, which are both nice to have. The Coda will limit your tire clearance to about 35-38mm (so says the Jamis help desk when I asked). I don't know if you could put a 47mm tire on it if you went to 584mm wheels like the Sequel has, but it's a possibility. With most Codas being equipped with disc brakes, you don't have to stick with the 622mm wheels. But if your goal is wider tires, then the Sequel is probably the better fit for you. It's generally a bit more modern all around, with the thru axles, a chainstay-mounted brake caliper vs. seatstay-mounted like the Coda has, etc. You'll pay more for those things, though.
I'm not all that familiar with the Sequel, but it looks like a solid bike. If price were no factor, I'd probably buy the Sequel. If my budget was tight...I'd probably have to think more about it. :-)